Sorry for the colors, I used an automatic export from a planner...
EDIT fixed now...
Radiant Aura is overslotted for your level IMO, you'll need some of those slots for Radiation Infection instead.
Neutrino Bolt could benefit from a 1 Acc/3 Dam slotting.
X-Ray Beam is not worth the power pick if you do that slotting for NB. Especially when you're neglecting to take Radiation Infection.
Mutation should not be needed and 2 recharges is very much overkill unless your team is hopeless. Of course, some people like having Mutation and it can help out, but it can easily be delayed to level 26 or later if you want it.
Electron Haze with just 1 slot isn't all that useful. And if you're going for Defense DeBuff then you'll want Irradiate instead.
Move Lingering Radiation up to level 12 (for exemplaring) and Hover to 8 or 10.
You'll probably want a Fly enhancement in Swift as it accepts those these days, either update the planner on your own or grab another planner.
Health needs no slots in it. You will not see much of a difference, especially with Radiant Aura in your build.
Thanks a lot Torch.
Radiant Aura I need well slotted since I use this character basically only for team play, however which slot you think could wait till later?
For the same reason I will keep mutation, but you're making me reconsider the double slotting. Makes sense to put in just one recharge reduction.
If I don't take X-Ray beam anymore, what should I be getting instead in your opinion?
Thanks again 
[ QUOTE ]
Thanks a lot Torch.
Radiant Aura I need well slotted since I use this character basically only for team play, however which slot you think could wait till later?
[/ QUOTE ]
I'd drop 2 Recharge and maybe replace 1 Healing with an Endurance Reduction. You should not need 3 Recharge in RA and 2 Heal should be sufficient.
[ QUOTE ]
If I don't take X-Ray beam anymore, what should I be getting instead in your opinion?
[/ QUOTE ]
Radiation Infection. RI is, along with Enervating Field and Lingering Radiation, one of the most important powers in Radiation Emission. Radiant Aura is (IMO) merely a patching tool for the times RI+EF+LR aren't enough (ie. you get mezzed or your anchor is killed).
While it takes a bit of time to activate it is very effective in cutting down incomming damage while it lasts. It is best used on whatever lasts the longest in a spawn, how you actually place it should be adjusted to the actual spawn and your team. 1 EndRed and 1-3 To-Hit DeBuffs (depending on how many slots you have left) will make it very useful, especially against EBs, AVs and GMs.
I would say if using the character for team play you need to play to the strengths of your set. Radation Defence is not a healing set. Your heal will never be good enough to do anything more than top up the incidental damage people take through the debuffs, the debuffs on the other hand, will really, seriously, keep people alive.
The mainstay of your debuffs is Radiation Infection, which is well worth taking, and slotting, with at a minimum an endurance reducer and three to hit debuffs. This will massively reduce the amount your team gets hit. Enervating field will then add to that, meaning that when they do get hit, they'll take less damage, and lingering radiation will mean that in addition to the bad guys hitting less often, and for less damage, they'll do it a lot more slowly. These powers are good, they really do work when combined together, and these are the powers that really make the set, not a (sorry) third rate heal.
Add all that together and you're really protecting your team in the way that Radation does it best, in addition to raising your teams tohit and damage output and generally making them kill stuff quicker.
I would then look, at that sort of level, at slotting radiant aura with three heals and maybe one recharge, which will give a decent topup to any damage that gets through the debuffs.
I would also favour taking powers that keep your team alive, prior to taking mutation. It's a good res, and lets face it no matter how good the team people do die occasionally, but I'd probably look at slotting it in later, and not bother slotting it.
(On the subject of the secondary, if you're looking for an AOE attack, Irradiate is a lot more team friendly than Electron Haze. It does good damage, it has a high base defence debuff, it's only real draw back is it is mele. Electron Haze offers itself out as an AOE Knockdown, it's actually Knockback, it's not a great power when you want everything to stay in your debuffs.)
Edited to add: Grant Invisibility isn't that great, you could easily lose that out the build and not miss it in my opinion.
Consider taking Radiation Infection early. I don't see it in your build anywhere. RI will cut down on your need to use your heal especially once you have 3 ToHit Debuffs in it.
Octavian Vanguard
@ohmsEU and @ohms 2
Badging character: Bimble on the Union server, Badgehunter.com and City Info Tracker.
Thanks a lot for all your feedback; I never took infection before because I thought two debuffs would be a real pain for endurance, but I can finally take stamina now, so I will be able to be more efficient with both the toggle debuffs. And from what I read I definetely underestimated it, because it intertwines its effects with those of Enervating Field more than simply adding to it like thought. Therefore I'll surely take it when I respec.
Concerning Grant Invisibility, it's great for ghosting missions with the team and fits the character, so I think I will keep it
Thank you very much, you're being invaluable help 
Since I am gonna get a freespec as a veteran reward soon, I would like to hear your opinions about this possible Rad/Rad Defender build... Only goes so far as level 24 since that is the level that I am now
Any suggestion will be appreciated
Exported from version 1.5C of CoH Planner
http://joechott.com/coh
Archetype: Defender
Primary Powers - Ranged : Radiation Emission
Secondary Powers - Support : Radiation Blast
[color=red]Level 01 : Neutrino Bolt[/color]
[color=blue]Damage[/color] ( 01 )
[color=blue]Range[/color] ( 7 )
[color=blue]Damage[/color] ( 15 )
[color=red]Level 01 : Radiant Aura[/color]
[color=blue]Healing[/color] ( 01 )
[color=blue]Healing[/color] ( 3 )
[color=blue]Recharge Reduction[/color] ( 5 )
[color=blue]Recharge Reduction[/color] ( 11 )
[color=blue]Healing[/color] ( 13 )
[color=blue]Recharge Reduction[/color] ( 21 )
[color=red]Level 02 : X-Ray Beam[/color]
[color=blue]Damage[/color] ( 02 )
[color=blue]Accuracy[/color] ( 3 )
[color=blue]Damage[/color] ( 19 )
[color=blue]Damage[/color] ( 23 )
[color=red]Level 04 : Accelerate Metabolism[/color]
[color=blue]Recharge Reduction[/color] ( 04 )
[color=blue]Endurance Recovery[/color] ( 5 )
[color=blue]Recharge Reduction[/color] ( 9 )
[color=blue]Recharge Reduction[/color] ( 13 )
[color=blue]Endurance Recovery[/color] ( 21 )
[color=red]Level 06 : Enervating Field[/color]
[color=blue]Endurance Reduction[/color] ( 06 )
[color=blue]Endurance Reduction[/color] ( 7 )
[color=blue]Endurance Reduction[/color] ( 9 )
[color=red]Level 08 : Mutation[/color]
[color=blue]Recharge Reduction[/color] ( 08 )
[color=blue]Recharge Reduction[/color] ( 11 )
[color=red]Level 10 : Electron Haze[/color]
[color=blue]Defense DeBuff[/color] ( 10 )
[color=red]Level 12 : Hover[/color]
[color=blue]Flight Speed[/color] ( 12 )
[color=red]Level 14 : Fly[/color]
[color=blue]Flight Speed[/color] ( 14 )
[color=blue]Flight Speed[/color] ( 15 )
[color=red]Level 16 : Lingering Radiation[/color]
[color=blue]Accuracy[/color] ( 16 )
[color=blue]Recharge Reduction[/color] ( 17 )
[color=blue]Recharge Reduction[/color] ( 17 )
[color=blue]Accuracy[/color] ( 19 )
[color=red]Level 18 : Grant Invisibility[/color]
[color=blue]Defense Buff[/color] ( 18 )
[color=red]Level 20 : Swift[/color]
[color=blue]Run Speed[/color] ( 20 )
[color=red]Level 22 : Health[/color]
[color=blue]Healing[/color] ( 22 )
[color=blue]Healing[/color] ( 23 )
[color=red]Level 24 : Stamina[/color]
[color=blue]Endurance Recovery[/color] ( 24 )
[color=blue]Endurance Recovery[/color] ( 25 )
[color=blue]Endurance Recovery[/color] ( 25 )
-------------------------------------------
[color=red]Level 01 : Brawl[/color]
[color=blue]Empty[/color] ( 01 )
[color=red]Level 01 : Sprint[/color]
[color=blue]Empty[/color] ( 01 )
[color=red]Level 02 : Rest[/color]
[color=blue]Empty[/color] ( 02 )
Thanks!