On Friday, August 3, [2018,] at approximately 1245 PST, Holtec International (a contractor for Southern
California Edison (
SCE)) was lowering a Multi-Purpose Canister (
MPC) loaded with spent fuel into the Cavity Enclosure Container (
CEC) of the
SONGS Holtec UMAX Independent Spent Fuel Storage Installation (
ISFSI) for purposes of dry storage. The canister was suspended from a Holtec Vertical Cask Transporter (
VCT). During the download, the canister encountered an interference with the
CEC divider shell and became bound in place. As a result, the downloader slings of the
VCT became slack while the
MPC was resting partially inside the
CEC.
Once Holtec became aware of the situation, the VCT towers were raised in order to restore tension in the rigging and to raise the MPC. The VCT was then adjusted, and the MPC was then safely lowered into the CEC and the rigging was disengaged.
There was no effect on the integrity of the canister or release of radioactive material as a result of this event.
This event meets the reporting criteria of 10CFR72.75(d)(1) in that the VCT, which is an important-to-safety component, was placed in a configuration which defeated its ability to perform its safety function. The VCT and associated rigging are described in Certificate of Compliance 1040, Technical Specification 5.2.c.3, which requires that lifting equipment shall have redundant drop protection features which prevent uncontrolled lowering of the load. By placing the VCT in the configuration of this event, the single-failure proof nature of the lifting devices was defeated. The VCT was no longer capable of mitigating the consequence of an accident, and there was no redundant equipment available and operable to perform the required safety function.
SCE made an original determination that the event did not require a report. However, SCE contacted the NRC [Region IV] on Monday August 6th and again on Tuesday August 7th to provide details of the event.
It has now been determined that the event is reportable under 10CFR72.75(d)(1) and this late report is being made.
Licensee notified RIV (Simpson).