You can request a service user in SVN and set as the same password in TAC if possible.
Ideally if SVN is integrated to AD, requesting as service user with non-expiry password and embed in the TAC configuration.
Or
In the SVN configuration, map the SVN username field to AD user name field and leave the password as empty so that it would ask the AD user password who ever logs in studio.
E.g. User name is TAC is fistname.lastname@company.com . User will login to studio using email id and password, after login it would ask another password that is user's AD password for validating SVN.
Let me know if this gives an idea.
