The regulations haven't changed since the new American units began construction. Regulations were supposed to be factored in to the cost/schedule estimates. Yet the original cost/schedule estimates turned out to be badly mistaken.

Maybe you weren't following closely enough...

John Ma, a senior structural engineer at the NRC was quoted on his stance about the AP1000 nuclear reactor:

"In 2009, the NRC made a safety change related to the events of September 11, ruling that all plants be designed to withstand the direct hit from a plane. To meet the new requirement, Westinghouse encased the AP1000 buildings concrete walls in steel plates. Last year Ma, a member of the NRC since it was formed in 1974, filed the first "non-concurrence" dissent of his career after the NRC granted the design approval. In it Ma argues that some parts of the steel skin are so brittle that the "impact energy" from a plane strike or storm driven projectile could shatter the wall. A team of engineering experts hired by Westinghouse disagreed..."

In 2010, following Ma's initial concerns, the NRC questioned the durability of the AP1000 reactor's original shield building in the face of severe external events such as earthquakes, hurricanes, and airplane collisions. In response to these concerns Westinghouse prepared a modified design... In May 2011, US government regulators found additional problems with the design of the shield building of the new reactors. The chairman of the Nuclear Regulatory Commission said that: computations submitted by Westinghouse about the building's design appeared to be wrong and "had led to more questions."; the company had not used a range of possible temperatures for calculating potential seismic stresses on the shield building in the event of, for example, an earthquake...

In November 2011, Arnold Gundersen published a further report on behalf of the AP1000 Oversight Group, which includes Friends of the Earth and Mothers against Tennessee River Radiation. The report highlighted six areas of major concern and unreviewed safety questions requiring immediate technical review by the NRC...

In 2012, Ellen Vancko, from the Union of Concerned Scientists, said that "the Westinghouse AP1000 has a weaker containment, less redundancy in safety systems, and fewer safety features than current reactors"....

In October 2013, Li Yulun, a former vice-president of China National Nuclear Corporation (CNNC), raised concerns over the safety standards of the delayed AP1000 third-generation nuclear power plant being built in Sanmen, due to the constantly changing, and consequently untested, design...

So, a bunch of NIMBYs hire a professional witness/fraud like Arnold Gundersen (who stated in Al Jazeera that "Fukushima is the biggest industrial catastrophe in the history of mankind") to keep doing what he's been doing for his entire career, while other anti-nuclear groups (I mean, 'league of concerned scienticians') dogpile on. Then the NRC dogpile on too, because the AP1000 might not be able to withstand a plane flying in to it (a standard requirement of any self-respecting electric generation plant), and so Westinghouse redesign the containment structure to mercifully get regulatory approval.

Then one of their major buyers (CNNC) and owners of derivative intellectual property (the CAP1400 reactor) begins to raise concerns about delays and lack of testing due to the constantly changing design. From my point of view, it just looks like Westinghouse couldn't catch a break. In other words, par for the course in the nuclear power generation industry.

These people don't give a damn about the environment, climate change, human lives or rationality. They're far too busy keeping up their image as an 'anti-nuclear friend of the earth', an identity they've spent most of their lives investing in.