Good engineers take the human factor into account and include backups in their designs to handle failure modes caused by the human factor. What they can't do i

Good engineers take the human factor into account and include backups in their designs to handle failure modes caused by the human factor. What they can't do is work around politics or budgetary constraints which force trade-offs between safety and cost. Anything can be made as safe as necessary, if you're willing to pay for the redundancies. When it comes to reactors on Earth, a very large proportion of the budget is diverted to bureaucratic paperwork, lobbying, and PR, which could instead be used to pay for additional safety measures.