i have a code that insert new page

i use Repeatable Read Isolation Level to avoid duplicate Insert

but i do a quick test that insert duplicate pages
Code:
using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew,
            new TransactionOptions { IsolationLevel = IsolationLevel.RepeatableRead }))
       {
            using (entities EFmodel = new entities())
...