[lstodd]

You sound like it's now forbidden to joke on the internets.

Besides, when one buries some mildly radioactive materials in 20 meters of ice with a median temperature of 230K or something like that, it just doesn't matter what neutron flux they release. And if they heat up, they would just sink deeper.

What matters is that that the neutron flux is adequately dissipated. Which it would be.