Transfer cask for spent nuclear fuel

A transfer cask for transferring a canister storing spent nuclear fuel, the transfer cask comprising:

• a transfer container having a space for accommodating the canister;
• a neutron shielding body arranged on an outer periphery of the transfer container to shield neutrons;
• and
• an opening/closing portion that is coupled to a lower portion of the transfer container and opens and closes the lower portion of the transfer container,
• wherein the opening/closing portion comprises:
• a support portion which supports the transfer container and in which the lower portion of the transfer container is placed and a first through-hole communicating with the transfer container is formed;
• a base plate on which the support portion is placed and in which a second through-hole through which the canister passes is formed;
• and
• a lid assembly having a first lid portion that opens and closes part of the first through-hole by rotating a first lid around a first rotation axis, and a second lid portion that opens and closes a remaining portion of the first through-hole by rotating a second lid around a second rotation axis.