This error generally occurs when the version of your cuda and tensorflow installed are not compatible. I also encountered the same Import Error while I was running tensorflow version 1.13.0 with my cuda 9. As I had installed tensorflow on a virtual environment with pip, I just had to uninstall the tensorflow 1.13.0 and install tensorflow 1.12.0 using following commands :
pip uninstall tensorflow-gpu tensorflow-estimator tensorboard
pip install tensorflow-gpu==1.12.0
Now everything is working for me.
You can fix the error by adding the following command to your '.bashrc' file.
Ubuntu :- 16.04 LTS
Tensorflow :-GPU 2.0beta1
cuDNN :-7.6.0 for Cuda 10.0
Here I used the conda to configure my system.