In October of last year, GE Hitachi first reported problems with cracks in the Marathon Control Rod Blades in older boiling water reactors. The cracks indicate that the blades may not be able to be used for as long as GE Hitachi had previously predicted.
Today, GE Hitachi issued an update:
GEH has determined that the design life, of D and S lattice Marathon Control Blades may be less than previously stated. The design life if not revised, could result in significant control blade cracking and could, if not corrected, create a substantial safety hazard…
Another factor to look at when the NRC is considering relicensing of older plants with boiling water reactors. (As well as being something to keep in mind with any project GE Hitachi is involved in.)