YEs, you can object to it although the university itself may decide to not allow you to go ahead, as that is at their discretion...but can be appealed. I refused Hep B when I was doing my midwifery at University in the UK and apart from a crazy nurse that called me and told me I was going to die if I didn't get it, it was all fine. I just signed the waiver.
If you look in to Hep B stats, even if you catch it, if you are healthy and look after yourself, you are unlikely to even become one of the 5% that need inpatient hospital care. Remember, the stats on Hep B don't show the overall health of the population before catching it. When you start digging, I'd rather be healthy enough to deal with Hep B, that contribute to ill health and STILL run the risk of catching it anyway, as vaccines are not 100% effective (no where close!).
If you don't want it, do not do it. Find a way round it. I'm currently applying for my US Visa (husband is American but we've been living here a few years) and although it will take me about 10 months longer plus a ton of paperwork, it is not worth sacrificing my principles, beliefs and health just for an easier application.
If they don't let you in without vaccines, this may be the worlds way of telling you it's just not for you!