The charity aims to fundraise over the summer to improve its seal unit by making the pool bigger and fitting a pump system in case any further rescues are needed.
The IAEA statement was released hours after Tepco temporarily shut down the cooling system in the second unit's spent fuel pool following the discovery of dead rodents near a transformer.
The 312-unit project's fifth floor is slated to include such amenities as outdoor kitchens, a salt-water pool and an organic garden where residents can grow their own vegetables.