So, I've devised a few tips and trick for the nuclear reactor not to explode 
or a reactor that'll burn out your best cables 
:
-Use neutron reflectors around uranium cells to boost the effieciency.
-Avoid using quad uranium cells, which are so efficient they'll blow your reactor in less than a minute, unless there are coolant cells and quad cells in columns.
-Using overclocked heat vents is the best but they self-destruct if there is nothing around to cool them, so use heat exchangers.
-It is recommended that you use RSH/LZH Condensators, since they take more heat than vents and only need redstone/lapis lazuli to recharge.
-Heat vents are also good since they also cool down the reactor and themselves, but they can self-destruct if left unattended.
-When your cables are burning out, then's the time to start using HV-Transformers.
-It is not possible to have a safe AND extremely efficient reactor. If you want both, then install multiple reactors.
This is what I have so far. For instance, here's an OK reactor type: http://www.talonfiremage.pwp.b…splezniebrr1r23mxpty0kav4
--> Edit: if someone know it and want to share it with me ... 
)
