Nureg-1150 is like a very big book that tells grown-up people about the dangers of accidents at nuclear power plants. This book has a lot of information about things that could go wrong at a nuclear power plant, like when there is a problem with something called the "core" or when the plant gets really hot.
People who work at nuclear power plants use Nureg-1150 to help make sure that they are doing everything they can to keep everyone safe. They also look at this book to make a plan in case something bad happens at the power plant.
The book is very important because it helps people to be prepared for any accidents that might happen at a nuclear power plant. Even if nothing bad happens, it is still important to know what could go wrong so that everyone can be safe.