TEPCO released a short handout this week that explains their plan for removing the damaged fuel at unit 4.
One assembly is considerably bent, both the body of the assembly and the lifting handle are damaged. TEPCO cites this as being from a work error before the disaster. Two additional assemblies have known leaks.
TEPCO plans to remove the damaged assembly using the overhead crane rather than the refueling crane. This would be a far less precise process. Their reasoning for using the overhead crane was due to the bent lifting handle. TEPCO says they will run a criticality estimate based on a scenario where a fuel assembly breaks open and fuel pellets spill out. It was not explained why that was not already completed.
The existing fuel transfer casks will be used for removing these three problem assemblies. It was also mentioned that unused fuel assemblies that were being stored in the pool will be transferred to the unit 6 spent fuel pool to save on space in the common pool.