Since it is on top of the fridge, I wouldn't think the placement would block the signal or cause intermittent loss. Start up of the motor could cause a problem but not necessarily.
If you want to experiment with this, here's an idea. Run an extension cord to the router from an outlet on a different electrical circuit than the fridge is on. If that solves the problem, then try using a surge suppressor with good line conditioning on the same plug it is in now. If that solves the problem you are in good shape. If not, return the surge suppressor to the store and look for other causes or another location for the router.
Depending on how old your router is, you might also just replace it and see if a new one solves the problem. If that doesn't help, then the problem was not likely in the old router. So, return the new one to the store.
There are many different reasons for intermittent dropouts and ping spikes such as cordless phones. So keep investigating until you find it. Some can be solved and others not. Sometimes it is as simple as changing the channel on the router. So try that too.