Re: Reverse the polarity of the Neutron flow.
Unlocking our telomeres would be much more likely to increase the rate of cancers than giving us immortality.
More realistically, it might give most of us a healthy life extending to 100, maybe 120 years. How successfully depends on how many of the diseases and failings of old age are caused by the biological senescence mechanism, and now many by other causes such as accumulating cellular mutations.
Alzheimers is not a certainty. I remember interviews with Jeanne Calment (she lived to 122, despite smoking heavily all her life!) and Harry Patch (the last veteran of WW1). Both were of sound mind when their bodies quit on them. So are the majority of people who (mostly) die in their 70s, 80s and 90s from causes related directly or indirectly to cellular senescence.
Wrt cancer: as other causes of death become curable or treatable, its incidence increases. It's also more likely the older we are, because of accumulating cellular mutations. Personally I'd take an increased risk of eventually falling to cancer, than the near-inevitability of falling apart in my 80s or 90s when my body's self-repair mechanisms start to turn off.
Immortality is not even conceptually attractive. However, a few more decades of reasonably enjoyable life most certainly is.