A very well researched account of the disaster and the remediation efforts that followed. If you want a good overview of what took place and how it affected the lives of those involved I would recommend. 
However, a few (relatively minor) issues. 
 Early on, the author describes boron as a material which would speed up a reaction, as opposed to slow it down. I know rationally this is a minor mistake due to the slightly confusing technical term, however it made me squint at every statement within the book wondering what other errors had been made and if I was not picking up on them. Comp unding this issue is the lack of in text citations - the bibliography is extensive so I don't understand why you would not reference in the text.
Another thing which bugged me was the contrast between the descriptions of Russians ("narrow Siberian eyes", tall and gaunt, austere) vs. the Americans (handsome and rich, going for runs before their volunteer work at the hospital). It was... Definitely a choice.