The new 2001's and the Eclipse-8's and the Eclipse's are part of the Diablo Canyon NPP upgraded warning system. They were the first ones to get the Eclipse-8. By the way, they are testing there system this weekend - two separate soundings I believe.
The Eclipse and the Eclipse 8 sound nothing like a 2001. The 2001 has an alerting frequency ~790 Hz. The Eclipse models alerting frequency is ~520 Hz - so they sound like T-121's or T-112's.