Vampires, Radiation, and Regeneration, Oh My Options

[Draco18s]

Not entirely correct. Radiation "uses the same mechanics given for pathogens".

This does not mean that it is indeed a Pathogen, and given that no other effect providing Pathogen or Toxin resistance applies to radiation, & radiation has several protective systems specifically for it, I would strongly argue that Rules as Written, a vampire's Immunity does not apply.

Nice catch.

[toturi]

Not entirely correct. Radiation "uses the same mechanics given for pathogens".

This does not mean that it is indeed a Pathogen, and given that no other effect providing Pathogen or Toxin resistance applies to radiation, & radiation has several protective systems specifically for it, I would strongly argue that Rules as Written, a vampire's Immunity does not apply.

The more I read the rules for Radiation the more I think we need a developer/writer to weigh in on the intent.

I can think of at least 1 protective system that functions the same for Radiation poisoning as for Toxins and Pathogens - the Chemical Seal. The chemical seal protects against the contact vector of Radiation poisoning. Although it does not give the wearer total immunity, at least he is immune to the contact vector of Radiation.

Also there is a curious statement that in the case of inhaled/ingested isotopes, implanted filtration systems could be used against it. Of course, in SR4, there are no such implants that work. At present, implants of similar effects do not work against Radiation poisoning because it does not have the inhalation vector(Tracheal Filter) or the Speed of Radiation poisoning is too fast(Nephritic Screen), not because they do not work against Radiation poisoning per se.

[Draco18s]

I think there you're looking at contact, ingestion, and inhalation vector toxins and poisons that are poisonous and toxic because they're radioactive rather than the defenses protecting against radiation in general.

See: Alpha Decay: Toxicity and The Health Effects and Body Response of Gamma Radiation.

[toturi]

I think there you're looking at contact, ingestion, and inhalation vector toxins and poisons that are poisonous and toxic because they're radioactive rather than the defenses protecting against radiation in general.

I do not quite understand your point. Radiation poisoning has contact, ingestion and irradiation vectors as per Pathogen rules on p129 Augmentation. So in order to be safe, you should need to be protected against all 3 vectors.

[Draco18s]

I do not quite understand your point. Radiation poisoning has contact, ingestion and irradiation vectors as per Pathogen rules on p129 Augmentation. So in order to be safe, you should need to be protected against all 3 vectors.

That depends. Contact vector means that you need to be in contact with the source in order to be effected (obviously).
Radiation doesn't necessarily come as all three at the same time (see Alpha Decay, "Even touching an alpha source is usually not harmful, though many alpha sources also are accompanied by beta-emitting radio daughters, and alpha emission is also accompanied by gamma photon emission.")
Gamma radiation is the only one that comes as irradiation vector (the most likely vector that the characters in this thread suffered), as alpha radiation is so easily blocked (but would cause harm if ingested, and the same substance in a fine powder would qualify as inhalation).
Beta emissions would be close proximity irradiation, but more likely come as ingestion or inhalation only; "Beta-minus (β-) radiation consists of an energetic electron. It is more ionizing than alpha radiation, but less so than gamma. The electrons can often be stopped with a few centimeters of metal. It occurs when a neutron decays into a proton in a nucleus; release the beta particle and an antineutrino. Beta-plus (β+) radiation is the emission of positrons. Because these are antimatter particles, they annihilate any matter nearby, releasing gamma photons. Therefore, they pose no direct risk, although the gamma photons released do."

[toturi]

That depends. Contact vector means that you need to be in contact with the source in order to be effected (obviously).

I understand, but I think my point still stands. Under the pathogen rules, there are certain vectors which are similar to the toxin vectors. Also whether am I looking at those radioactive substances as toxic and poisonous is irrelevant, under Radiation Notes in Arsenal, certain "implanted filtration systems" are implied to work "in the case of inhaled or ingested isotopes", although I'd be the first to admit that I have yet to find a SR4 filtration implant that actually works.

Assume for an instance that such an implant exists, then in the case of ingestion or inhalation(although Radiation Poisoning does not have an inhalation vector), the penetration of the Radiation poisoning would work against this implant as per the rules.

[Draco18s]

I don't know
*Quickly mashes the "I believe" button.*

[Falconer]

I agree with this fully. In my games, Regeneration can heal any form of damage, magical, nervous, or otherwise (exception being Drain, because Drain specifically cannot be healed by magical means, & Regeneration is a paranormal ability).

This is specifically a lousy house rule.

There should be SOME damage that regeneration can't fix forcing them to utilize more mundane or natural healing methods. You simply turn regeneration into an automatic... I don't care what hurts me, in a few seconds it all regenerates anyhow. (at a meager 2 boxes a turn... that's full healing in 15s).

That nonregenerable damage doesn't come from any 'nerve' damage. But only from CENTRAL NERVOUS hits.
EG: brain & spinal cord. Even now... we regenerate localized nerves all the time when we cut ourselves and such, it's the central hits which cause of major issues and we don't naturally heal.



Even ItNW has a specific condition where any damage caused by allergies bypasses it. Hell as a house rule, I'd suggest that any damage caused by immunities wouldn't regenerate either. (EG: if staked they stay staked until stake is removed).


And my comment on munchkinism is more to the effect of. You need to watch your players power levels. Problems come not from powerfull players, but from when one player is far above the others. From the sounds of it, the OP has 1 problem player, and the rest are getting along nicely.


Also -4 penalty for being in the sun is a pain yes, but it is a bearable pain. If you view the sun as radiation... then actual radiation from radioactive sources may qualify as light (gamma). In which case, then the radiation damage should have +2DV against the vampire.

[Muspellsheimr]

You did not read clearly.

I said that all forms of damage can be healed through the Regeneration power. I did not say I changed anything else. Regeneration ceases to function while exposed to an allergen as normal. Further, Vulnerabilities create creature-specific exceptions not covered under Regeneration.

I have considered removing Vulnerabilities, instead having all allergen's function as such, but will probably not do so.

[Rasumichin]

Further yes I do believe it is foolish to allow vampires in games as by necissity they will either be amazing or they will hobble the rest of the team and force them to work around the vampire.

Why is it necessary that they are amazing?
Unlike in other settings, no SR vampire has been a vampire for more than 70 years and even these cases should be rare, and would not be represented properly by a 400BP character.
These are likely the equivalent of an average person who got infected a few years ago, and these are without a doubt far from being the legendary monsters they are presented as in many other works.

A vampire will be stronger than an average human, but that goes for practically all runners as well.
Will a 400BP vampire be stronger than other 400BP characters?
Unlikely, given roughly the same amount of optimization for all players.
There's amazing benefits, but strong drawbacks as well.

No 'ware at chargen, no geneware ever, no less than delta grade 'ware ever either, lower starting Magic, tighter restrictions on BP because 100 points have already been spent, problems with finding medical assistance when they get hit by something they cannot regenerate, need to distribute otherwise needed ressources for spell sustaining on Alleviate Allergy (twice at daytime) or suffering the consequences, need to hide vampiric nature or suffer the consequences, need to come up with nourishment, problems with water.

Many of these restrictions can be worked around and if the player is smart enough, the benefits will outweigh the drawbacks, but that goes for all character types.
Open build point systems like SR4 always entail the risk of unintentionally crippling your character in certain regards, especially if you try too hard to powergame.
It's a bit harder to come up with a vampire who isn't overspecialized or hurt too much by vampiric drawbacks, but it's entirely possible.

That nonregenerable damage doesn't come from any 'nerve' damage. But only from CENTRAL NERVOUS hits.
EG: brain & spinal cord. Even now... we regenerate localized nerves all the time when we cut ourselves and such, it's the central hits which cause of major issues and we don't naturally heal.

But specifically excluding these is kinda problematic in a system that does not have any mechanic for targeting specific body parts (yes, there's called shots, but even they are heavily abstracted).
Most of the time, it will be entirely pointles that this restriction exists.

As i wrote previously : killing regenerating critters by going for a headshot was a rule needed when Regeneration meant that you could heal any amount of damage done to you at the end of the combat round.
In combination with SRs abstract damage system, it lead to more than wonky mechanics, completely randomizing any fights against regenerating enemies
And not representing "going for a headshot" either.
It was more like "shoot it again and pray it stays down this time" or "save the stun rounds for the shapeshifters".
Good riddance.

Even ItNW has a specific condition where any damage caused by allergies bypasses it. Hell as a house rule, I'd suggest that any damage caused by immunities wouldn't regenerate either. (EG: if staked they stay staked until stake is removed).

That's actually already the case : as long as the allergen is present, there's no Regeneration, so they have to pull out the stake first.
Which is why barbed wooden arrows or crossbow bolts work so great against vampires.

And my comment on munchkinism is more to the effect of. You need to watch your players power levels. Problems come not from powerfull players, but from when one player is far above the others. From the sounds of it, the OP has 1 problem player, and the rest are getting along nicely.

From the sound of it, the OP has no problem player, just a technical question that doesn't really matter in his game, as the vampire PC could easily get medical treatment if necessary.

Also -4 penalty for being in the sun is a pain yes, but it is a bearable pain. If you view the sun as radiation... then actual radiation from radioactive sources may qualify as light (gamma). In which case, then the radiation damage should have +2DV against the vampire.

Even though the sun emits radioactivity, it's rather doubtful that this is the reason why it hurts vampires...

[Falconer]

And I said it was a lousy house rule. There should be some damage that the regeneration power cannot heal. And the regeneration power specifically lists central nervous hits as the only one. Which IIRC you said you removed that limitation allowing any and all damage to regenerate (EG: give it 15s (5combat turns) and you'll be back to full health no matter what... excepting drain). I stand by my guns on that one.



As far as regeneration and allergens. Could you please tell me where you found the bit about not regenerating in the presence of allergens. I was looking over my SR4a book, when I wrote the post and couldn't find it.

[Rasumichin]

And I said it was a lousy house rule. There should be some damage that the regeneration power cannot heal. And the regeneration power specifically lists central nervous hits as the only one.

That, and any magical damage.
Which i certainly wouldn't remove, as by now it's the only type of damage that will, under usual circumstances, effectively not be affected by Regeneration, as there is no hit location system of any kind.
Of course, magic being the only way to kill regenerators only holds true if allergens aren't present and you don't inflict enough damage in one round to drive the critter/character so far below physical overflow that even Regeneration doesn't help anymore.

As far as regeneration and allergens. Could you please tell me where you found the bit about not regenerating in the presence of allergens. I was looking over my SR4a book, when I wrote the post and couldn't find it.

Has this been removed in SR4A?

In the SR4 BBB, the last sentence of the Regeneration power reads :
"If the critter has an Allergy, the critter cannot
regenerate damage until the allergen’s presence is removed."

Removing this part would be a great mistake in my opinion, as it would restrict mundanes to making (strictly speaking mechanically impossible) headshots when fighting vampires.

I wonder how Vulnerability works out in this regard?
I recall something about damage from a substance a critter is vulnerable to being exempt from Regeneration altogether (on top of other effects), which would make this a serious weaknes.
This wouldn't apply to any Infected except goblins and banshees, of course.

[Muspellsheimr]

Regeneration (Paranormal)
Type: P • Action: Auto • Range: Self • Duration: Always
A critter with Regeneration rapidly heals any Physical
damage. At the end of a Combat Turn, make a Magic + Body
Test. Each hit regenerates 1 point of Physical or Stun damage.
If a critter has already taken enough damage to enter into Physical
damage overflow, the critter is not considered dead until it has had
a chance to make a Regeneration Test. After a critter has made a
Regeneration Test, if the damage overflow is still greater than the
critter’s Body attribute, then the critter is dead.

Certain types of damage cannot be regenerated from this
power. Damage to the brain or spinal cord (for example, from a
called shot to the head) cannot be healed this way. Likewise, magical
damage from weapon foci, combat spells, critter/adept powers,
or other magic may not be healed through Regeneration. If the
critter has an Allergy, the critter cannot regenerate damage until
the allergen’s presence is removed.

What I have done is simply remove the text in red. Even the most powerful creatures with Regeneration will not normally heal more than 5 or 6 points of damage per Combat Turn. Thus, even without damage types being exempt from Regeneration, it gives a good deal of staying power, but is quite a ways from making a character "immortal". It is still quite easy to kill such creatures, as damage output can very easily exceed the healing rate (if it doesn't, you are by yourself & a horrible shot).

Also, for those interested.

Vulnerability (Mundane)
Creatures with a vulnerability to a specific substance take
additional damage from weapons made of the substance. Increase
the Damage Value of all attacks with the substance by 2. Weapons
made of a substance to which the creature is vulnerable bypass any
Immunities that it may have. Damage taken from a substance to which
the creature is vulnerable cannot be healed by Regeneration or magic.

[Muspellsheimr]

Which IIRC you said you removed that limitation allowing any and all damage to regenerate (EG: give it 15s (5combat turns) and you'll be back to full health no matter what... excepting drain).

Except, of course, unless you are dealt enough damage that after making your Regeneration test, you are still dead - in which case, you don't get any more tests. Which is rather easy to do.

As for the healing, being a passive ability, it is more effective than Magical healing + First Aid, but those can also easily result in a character being at or near full health in a similar time frame, and are more versatile in that they can be used on others.

[Totentanz]

Everybody else seems to have the RAW/RAI angle sewn up, so I'll take a different approach.

What do you want for your game? What is good for the story? Dumpshock has a tendency to wallow in the RAW crap pit while mud wrestling with the "my gaming is better than yours" pig. Neither is productive.

Do you want, as others have suggested, to compensate the vampire player for tolerating having his character gimped through such an epic story line? Do you want to attempt to sew dissension in the team by having the vampire get off scot free (I think any team worth their salt wouldn't bit on this one, but YMMV)? Do you want, as others have suggested, to punish the stupid munchkin (I think this is just plain lousy, personally)?

This is one of those times when you earn your GM stripes by making a hard call. You can hide behind rule books, or you can be a badass GM and consider your players' and your story's needs and come up with something memorable and fun for everyone involved. Do the latter.

If you want a few starting off points, how about these:

1: The vampire is treated by the deep pockets and connections of their employer. During the course of the treatment they discover the radiation might have mutated the HMHVV into a new strain. Will the employer and his allies stay loyal, or will they attempt to exploit the PC's? Can the PC's take the chance of the latter?

2: Regeneration more or less saves the vampire's butt. While he is bringing flowers and chicken soup to his friends, their safe houses and caches are raided by somebody. What now? He has a brief but stressful opportunity to shine while his team-mates cheer him on from their beds. Not a bad turn around for getting gimped hard the whole last story.

3: The advanced medical team has an idea to create a regenerative cure from the radiation-exposed virus in the vampire's body. The team might make a full recovery, but they might end up vampires or dead from the experimental treatment. The vampire would have to undergo extensive and painful gene therapy and tissue harvesting, and might suffer irreparable damage or death from helping his friends, with no guarantee of success.

None of these might appeal to you, but the seed is there. Take a rules-related issue and turn it into an opportunity to roleplay and deepen the characters. Maybe give the team a chance to walk away with some unique toy like a gene therapy technique that arose from their treatment. They get some little perk no where in the book for their sacrifice. Figure out something that fits your style and don't be afraid to go beyond the rules or change them to tell a good story. That means one your players will enjoy and remember, too.

[Mirilion]

Everybody else seems to have the RAW/RAI angle sewn up, so I'll take a different approach.

What do you want for your game? What is good for the story? Dumpshock has a tendency to wallow in the RAW crap pit while mud wrestling with the "my gaming is better than yours" pig. Neither is productive.

Do you want, as others have suggested, to compensate the vampire player for tolerating having his character gimped through such an epic story line? Do you want to attempt to sew dissension in the team by having the vampire get off scot free (I think any team worth their salt wouldn't bit on this one, but YMMV)? Do you want, as others have suggested, to punish the stupid munchkin (I think this is just plain lousy, personally)?

This is one of those times when you earn your GM stripes by making a hard call. You can hide behind rule books, or you can be a badass GM and consider your players' and your story's needs and come up with something memorable and fun for everyone involved. Do the latter.

Very nice, Totentanz. Whenever in doubt, be awsome, that's the way I try to do it. Rules take second place.

Anyway, perhaps you could say that the medical staff discoveres a malignant tumor inside the vampire. It is a cancerlike thing, growing rapidly, appearantly originating from radiation-mutated brain cells and spreading along the nervous system. They are totally stumped, but one of the more experienced ones suggests to the vampire personally to go see an "expert", an older vampire mage. The attempt to locate this mage should be a mini-mission in itself. The mage is not unfriendly, and helps the vampire by suggesting a course of action : drinking the blood and essence of a willing, totally pure mortal. The mage treats the tumor as a paranormal, infected beast that needs to be weakened and killed. The pure blood, freely given, will remove the taint that allows it to grow. The old mage is at odds with most modern research about this, but his methods work. Now the problem is finding a pure person that can freely give it's blood (doesn't have to be to the death, but it has to be more than a drop). At the end of the conversation, the old mage says that the young vampire now owes him a favor. He will collect on it sometime in the future. Pure, by the way, means just that. You have to find a saint-like person that is able to freely give his or her blood.

[Rasumichin]

Thanks for quoting the text on Vulnerability.
Seems as if banshee hunters should stock up on tonfas now...

As far as regenerating magical damage is concerned, i wonder wether damage by critter powers also refers to natural weapons?


Regarding the interaction between radioactivity and magic, this has always seemed odd to me, aside from background count caused by radioactive polution and the immediate damage done by exploding a nuke.
To me, the whole "there's some mystic interaction between nukes and magic" thing always appeared as a handwave to explain certain aspects of the setting that "had to be there" for plot reasons, be it the torporific bugs in Chicago or the local containment of the various nuclear strikes and meltdowns that have appeared throughout SR history.
Libya, India, Pakistan, Chicago as well as several reactor meltdowns, most of which either seem to have been contained locally more than could be expected, have done less damage than could be expected or both, which has always been handwaved by saying "it's magic and it somehow interferes with nuclear explosions".
This always struck me as a rather unsatisfying attempt to establish limited post-doomsday settings.
Too much applied phlebotinum for my taste.

If i wanted to include interactions between magic and radioactivity that go beyond the usual BGC (which will already hamper both Regeneration and Immunity to Pathogens and Poisons greatly), i'd first try to flesh out this aspect of the setting further and try to come up with an explanation for it that goes beyond "that's just the way it is".

[Neraph]

I stand by my statement that if you allow vampiric PC's you deserve whatever moronicness your little munchkin monsters try and justify.

You're very open-minded.

I know radiation can cause the Magics to get weakened a-la Fluff (I apply background count in affected areas and people, aspected of course, it is powerful, just not the kind of power most can use).

Absolutely. Street Magic, page 121's sidebar about Domain Examples lists Hiroshima and Nagasaki's blast sites as Rating 6 Backround Count. The Cermak Blast Zone in Chicago on the next page's sidebar is a Rating 7 Mana Warp. Page 168 of Augmentation lists Aura Deficiency Syndrome as a possible effect for Awakened members who are irradiated. Radiation is a Really Bad Thing for Awakened subjects; even Radiation Mages are not neccessarilly protected from their own preferred element.

How is Radiation treated any different from a disease as far as game mechanics is concerned?

I believe I had a thread not too long ago espounding the virtues of TPK-ing (Total Player Killing) with radiation.

So, no offense to any of my esteemed fellow dumpshockers, my opinion is that because we're playing the game, mechanics seem to indicate radiation is regenerateable.

One caveat: damage to the brain or spinal cord cannot be regenerated. That's the ONLY mechanical angle I could see being relevant (because it's possible to get irradiated enough to damage the central nervous system), but I'd still have to be convinced of a good reason to handle radiation in a manner other than a pathogen, such as those to which vampires are immune.

The only problem I see with this logic (and it is very sound logic that many seem to miss) is that we are supplied hard-rules for allowing radiation to inflict backround count; hence, radiation can, in fact, impede Regeneration and other magical abilities.

Regeneration isnt so overpowered anymore either.

I assume that you mean here you do not know how Regeneration is overpowered. Allow me to demonstrate: a creature with Regeneration is not actually dead until he has a chance to roll for Regeneration, and cannot Regenerate when exposed to an allergy. So, for the sake of arguement, we have a vampire. He takes 100 boxes of Physical damage, which he will not be able to survive, but one of his teammates sticks his corp--body with a toothpick, stopping the Regeneration Test and putting the vampire into a state of suspended animation (S/A) until the toothpick is removed. Until then, you can treat the S/A vampire as any normal character, since he is not dead yet. Mitigate the damage through First Aid and Medicine until you drop it down sufficiently, then remove toothpick.

Perhaps you could house rule that exposure to radiation makes a vampire character's skin sparkle. (IMG:style_emoticons/default/smile.gif)

No.

[Neraph]

Previous post, part 2!

As far as the GAME is conserned "Radiation damage" is damage and if the sickness is listed under pathogens or diseases (I don't have the books at hand) the Vamp had hardended armour againt it at twice his magic rating, Regn works unless there are other factors involved (background count etc.).

I would not allow the Vampire's Immunity (Pathogens) to work against the secondary effects of radiation, since radiation works like a pathogen, yet is not a pathogen itself. The Devil is in the details.

Until the character has reduced the Power to 0, he will continue to suffer from the negative effects.

Close, but no. Until the Power is reduced to 0, he will continue to be exposed to the effects of Radiation, which, according to page 168 of Arsenal, can become cumulative. This leads rapidly to Walking Death Syndrome.

Not entirely correct. Radiation "uses the same mechanics given for pathogens".

Nice to see someone else got it too.

Even though the sun emits radioactivity, it's rather doubtful that this is the reason why it hurts vampires...

Actually, you may have finally broken the code. Every roughly 8 minutes, everyone on the day side of the Earth is given a full body X-ray, even inside. It's less inside, and less in cloudy weather, but still there.

... "expert", an older vampire mage. The attempt to locate this mage should be a mini-mission in itself. The mage is not unfriendly, and helps the vampire by suggesting a course of action : drinking the blood and essence of a willing, totally pure mortal.

Sounds like an African witch doctor telling the AIDS people to sleep with virgins to get rid of it to me (which they actually still do).

[Starmage21]

I assume that you mean here you do not know how Regeneration is overpowered. Allow me to demonstrate: a creature with Regeneration is not actually dead until he has a chance to roll for Regeneration, and cannot Regenerate when exposed to an allergy. So, for the sake of arguement, we have a vampire. He takes 100 boxes of Physical damage, which he will not be able to survive, but one of his teammates sticks his corp--body with a toothpick, stopping the Regeneration Test and putting the vampire into a state of suspended animation (S/A) until the toothpick is removed. Until then, you can treat the S/A vampire as any normal character, since he is not dead yet. Mitigate the damage through First Aid and Medicine until you drop it down sufficiently, then remove toothpick.

Actually, I didn't say it couldn't be overpowered at all. I stated that it wasn't so bad anymore, implying a comparison to how it functioned in older editions of Shadowrun(3rd specifically). So yes, the above example provided by you is definitely an extreme example of how it could be abused, so thats something of a slippery slope argument.

[Neraph]

Actually, I didn't say it couldn't be overpowered at all. I stated that it wasn't so bad anymore, implying a comparison to how it functioned in older editions of Shadowrun(3rd specifically). So yes, the above example provided by you is definitely an extreme example of how it could be abused, so thats something of a slippery slope argument.

There's no slippery slope; that's exactly what the rules say you can do.

[Starmage21]

There's no slippery slope; that's exactly what the rules say you can do.

Yet, as an extreme example of such, what you have stated fits perfectly the definition of a slippery slope argument, a logical fallacy. Just because it CAN happen, doesnt mean that it will.

[Draco18s]

Not realy

The heart of the slippery slope fallacy lies in abusing the intuitively appreciable transitivity of implication, claiming that A lead to B, B leads to C, C leads to D and so on, until one finally claims that A leads to Z. While this is formally valid when the premises are taken as a given, each of those contingencies needs to be factually established before the relevant conclusion can be drawn. Slippery slope fallacies occur when this is not done--an argument that supports the relevant premises is not fallacious and thus isn't a slippery slope fallacy.

Emphasis mine

However, it is Cherry Picking.

[Starmage21]

Not realy



Emphasis mine

However, it is Cherry Picking.

thanks for setting me straight

[Patrick Goodman]

Generally the player is pretty good about avoiding munchkin issues, which is why I let him play the vampire. He's not only done well in that respect, he's kept it the most professional PC in the group. We simply had a disagreement over which way regeneration would go with respect to radiation, and I didn't have a pressing reason to actually keep the vampire radiation damaged (not even "smack down the munchkin"), so I sought second opinions here.

Late to the game, but thought I'd chime in. I should preface this by saying that I prefer a much more cinematic approach to things, and this colors my judgment a great deal. I also feel like Infected PCs were a dire mistake and don't believe anyone should really use them. I'm prejudiced about this, however, so take my commentary with a grain of salt.

However, since you don't have a quality-control issue with the player, there's not much reason to be draconian for the sake of being draconian. I don't know that there's anything in particular that would keep the vampire from regenerating from radiation damage as from any other damage. The immunity to pathogens and poisons would not, IMO, apply; he'd take the full damage from the radiation, but he'd be able to regenerate it.

Not really. They weren't directly exposed to fallout or bomb material (well, one PC was, but he wasn't a vampire). The x-ray flash from the fizzle wouldn't cause the vampire's body to become radioactive, though it'd inflict radiation burns. The neutron burst would cause some activation of his atoms, but the dosage from that would be minor compared to the prompt x-ray and neutron dose, and the now-radioactive isotopes in him would mostly have very short half-lives.

That being said, however, I'd also rule that the radiation would trigger his allergy to sunlight, so he'd be dealing with that on top of his radiation burns. Additionally, until he was out of the hot area, he wouldn't be able to regenerate, since he can't regenerate allergy-related damage with the allergen still present.

There is a not-insignificant chance that this has all already been said, but I haven't read the whole thread, so bear with me, please.