First of all, ABWR has a poor track record. The ones in Japan, such as the Kashiwazaki-Kariwa NPS, suffered more shutdowns due to malfunction than other NPS in Japan. There were only 3 power plants that had operating ABWR reactors, all in Japan and all are still in shutdown since the Fukushima disaster, while other reactors have been reactivated. The construction for all other planned ABWR around the world have been postponed, just like NP4.
Also, instead of GE supervising the design and construction, NP4 was designed and built by contractors and their subcontractors without proper supervision. As a result the foundation for the reactor is already cracked. Taipower even altered the design without submitting it for approval. As a result, GE refused to vouch for NP4’s construction standards.
There was a host of issues with NP4’s construction, which Control Yuan found and put into a report. That report was what prompted President Ma to terminate NP4 in the first place.
NP4 has to be scrapped. If they are going to build a new one, there are better Gen III+ reactors by now, which all new nuclear power plants will adopt.