One second = 20 ticks.
No idea about the reactor data you got thou.
If Minecrafts using a crapton of memory and or cpu T/s Ticks per sec drops. Do you have an older or non gaming computer? Or *shudders* a mac? Being near the reactor might increase lag and thus drop your T/s
After some testing - it seems that reactor, indeed, use 29 t/seconds, but things get strange on short cycles and/or big EU/t fed into small storages.
For example, even if reactor works less than second, it will consume uranium cells as it was run full second, but will produce less electricity.
The reactor produces 20 times the EU/t shown in the reactor planner in a second. For example, a reactor producing 120EU/t will produce 2400 EU in a second.
hmmm my calculator says that a 120EU/t reactor should produce 40.000EU in 16,666.
i also don't think that the reactor has a different behaviour than any other generator, so 1s = 20ticks should apply here.
there are two differences though. first, the reactor "ticks" in 1s intervals and it seems to completely ignore short redstone impulses, so it could be difficult to time it in t rather than s. this could also cause the strange behaviours you mentioned, since minecraft works with t and the reactor with s.
second, the reactor always works. it doesn't shut off when no one takes the energy and it doesn't have a internal storage like other generators.
i think it's highly possible that your results are influenced by those behaviours.
on another sidenote: i noticed with my own reactor, that it doesn't seem to produce a constant EU/t ratio. when spamming my EU-meter at the output it most of the time says 1534EU/t and sometimes a single impulse over 1600EU/t. in a long run that gives me perfectly 1560EU/t, but it could cause problems in a small scale system like yours.
Minecraft runs in "ticks". Effectively, everything is "round-based" and updated x times during a second. Quite all games work like that, though their tickrate/framerate differs.
In case of minecraft, the game is hardcapped at 20 ticks per second. This means, if you FPS >= 20, you will run at these 20 t/s. If your computer is slower, however, your minecraft will run in "slow motion", aka less then 20 t/s.
The reactor uses a lot of CPU and thus only calculates it's inventory every 20th tick (= once per second, on a normal-speed computer), whilst saving the "produced energy" into a variable and emitting said energy every single tick (like a normal generator).
If a Reactor produces 120 EU/t, it does emit 120 EU every single tick. It does, however, only update itself every full second.
If you PC runs slower (<= 20 t/s), your whole MC world will run slower. If you, f.e. got 10 FPS, all machine operations will take 2x the time.
You can watch this interesting effect when playing on an overloaded server. I once played on IR with a dupe-bug lagging the crap out of the server. Smelting one item in the Electric furnace took ~30 seconds realtime, because the server itself was running at <5 FPS. Happened QUITE some time ago, somewhen around IC1.
A reactor will check for redstone only once each full second.
If this check happens during the deactivated-redstone-phase, it will fire up and run for one second until noticing you turned redstone on again.
Vice versa, if you deactivate redstone and reactivate it BEFORE the reactor checks, it will not react.
Not semi-random 
A reactor will check for redstone only once each full second.
If this check happens during the deactivated-redstone-phase, it will fire up and run for one second until noticing you turned redstone on again.
Vice versa, if you deactivate redstone and reactivate it BEFORE the reactor checks, it will not react.
Not semi-random
Good to know since the Reactor is partially undecompilable. So i no longer need to update the Redstonesignal on Chunkload.
BTW my Bucket-CASUC exploded on Chunkload, even when Coolant was constantly ON and at Maximumrate (550 ms). It must have smolten a Part of my RP-Contraption. Next Time i use a Timer, which is not resetting on Chunkload, so i will use a RP-Computer for my CASUC Mk III.
Good to know since the Reactor is partially undecompilable.
http://pastebin.com/qKrhH7UU
You're welcome. That's going to be fully refactored anyways, for the 2.00 Reactor API.
