Pros
TerraPower compensates very well, the mission of the company is interesting, and the office has a relatively collegial, casual atmosphere.
Cons
The "engineer" review already posted here hits the nail on the head. Management at this company is really horrible. They are making bad decisions for the company, behave unethically, and are not at all focused on taking care of employees. Politics in the office are incredibly unhealthy - gossip, backstabbing between projects and groups, support staff being treated with disrespect, etc. A few individuals in management are allowed to do whatever they want at the expense of the best interests of the company and others. There are almost no women in technical disciplines, and those who are hired quickly leave because conscious and unconscious bias from several key decision-makers eliminates any chances they would otherwise have of a healthy, successful career. The company is not prioritizing work well, and this creates a feeling of constant chaos at the working level. They are building incredibly complex schedules for their projects that have far more detail in them than what's warranted for where they are in their R&D design cycle; and those schedules end up being really wrong, so they re-do them repeatedly. It's incredibly taxing on the engineers and a waste of time. The CEO is completely absent from the company, and the President is not at all trusted by employees. Employee morale is incredibly low, and in most cases the only reason more employees have not left yet is they either really want to be a nuclear engineer in Seattle (and this is the only game in town) or they are paid well enough that they really struggle to give up the big paycheck.