YA book/series. Main character was popular boy who was severely injured in nuclear meltdown on a school trip, but was saved by a doctor who made him either a cyborg or mixed him with an animal

[Toby]

Read this as a kid, published pre-2010 but not entirely sure of the date as a whole

[Kris]

Monster Republic by Ben Horton?

https://www.worldcat.org/advancedsearch > Keywords: nuclear school trip | Subject: science fiction | Juvenile | Fiction | Book | English