One way to keep things moving along at a good clip is to do things in parallel. When it is done on a computer chip it is called pipelining.
So here is one way to pipeline the research.
Every test reactor station has one set of power supplies. It should have 3 reactors so that:
1. One is operational for testing.
2. One is being modified.
3. One is cooking out preparatory to testing.
Testing then can go on almost continuously.
Since the power supplies are the major cost driver for a test set up designed for continuous operation, and because the supplies will not change much with time, sharing the supplies with three nearly identical reactors should give a significant time advantage without much added cost. In fact cost per hour of use will decline with more intensive use since you are paying for less idle time.