<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>worldvoyageur</author><text>Tritium is a natural byproduct of CANDU fusion reactors, of which there are some 25 or so in operation globally, mostly in Canada.  CANDUs use heavy water as a neutron moderator (D20 instead of H2O), making T2O a natural byproduct.&lt;p&gt;Though most of the reactors do not harvest the tritium, a small number do.&lt;p&gt;CANDU operators have long been ready to make the capital investments in tritium harvesting, once demand materializes.  ITER has long been seen as a potential major source of tritium demand.</text><parent_chain><item><author>anonuser123456</author><text>&amp;gt; What&amp;#x27;s the catch this time?&lt;p&gt;This is D-T fusion.  Which means you have to have T.  Which currently comes from fission reactor and has a half life of 15 years.&lt;p&gt;So the plan is to use a molten salt blanket with Be to breed T.  But Be isn’t scalable for consumption, so maybe lead eventually.  That’s probably do-able, it just slows down the rate new reactors can come online since Pb is not as good a neutron multiplier.&lt;p&gt;Once they breed extra T, they have to capture and refine it.  Hydrogen is very corrosive and hard to work with… and T is radioactive hydrogen.  Again, probably doable.  But guess what?  Refining spent nuclear waste in fission reactors is also do-able.  It’s also super expensive.&lt;p&gt;And they still need a containment vessel that will withstand the wear and tear from sitting next to a mini hydrogen bomb all day.&lt;p&gt;These challenges are likely all surmountable.  But are they surmountable AND cheaper than existing nuclear or other energy sources?  Meh?</text></item><item><author>shmageggy</author><text>These university press releases are always very positively framed. This one makes the new magnet seem incredibly promising and fusion seem like almost an inevitability now, but decades of failure have us conditioned for skepticism. What&amp;#x27;s the catch this time?</text></item></parent_chain></comment><story><title>MIT-designed project achieves major advance toward fusion energy</title><url>https://news.mit.edu/2021/MIT-CFS-major-advance-toward-fusion-energy-0908</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>mcswell</author><text>&amp;quot;Hydrogen is very corrosive and hard to work with&amp;quot;  Corrosive compared to what?  You can put it in a rubber balloon and hand it to a kid.&lt;p&gt;&amp;quot;T is radioactive hydrogen&amp;quot;: True, it emits low energy beta radiation, which is an electron, and is stopped by a sheet of paper.  I used to have a wrist watch with a tritium dial; I haven&amp;#x27;t died of cancer yet.</text><parent_chain><item><author>anonuser123456</author><text>&amp;gt; What&amp;#x27;s the catch this time?&lt;p&gt;This is D-T fusion.  Which means you have to have T.  Which currently comes from fission reactor and has a half life of 15 years.&lt;p&gt;So the plan is to use a molten salt blanket with Be to breed T.  But Be isn’t scalable for consumption, so maybe lead eventually.  That’s probably do-able, it just slows down the rate new reactors can come online since Pb is not as good a neutron multiplier.&lt;p&gt;Once they breed extra T, they have to capture and refine it.  Hydrogen is very corrosive and hard to work with… and T is radioactive hydrogen.  Again, probably doable.  But guess what?  Refining spent nuclear waste in fission reactors is also do-able.  It’s also super expensive.&lt;p&gt;And they still need a containment vessel that will withstand the wear and tear from sitting next to a mini hydrogen bomb all day.&lt;p&gt;These challenges are likely all surmountable.  But are they surmountable AND cheaper than existing nuclear or other energy sources?  Meh?</text></item><item><author>shmageggy</author><text>These university press releases are always very positively framed. This one makes the new magnet seem incredibly promising and fusion seem like almost an inevitability now, but decades of failure have us conditioned for skepticism. What&amp;#x27;s the catch this time?</text></item></parent_chain></comment><story><title>MIT-designed project achieves major advance toward fusion energy</title><url>https://news.mit.edu/2021/MIT-CFS-major-advance-toward-fusion-energy-0908</url></story>