Don Mosier | Rimini Road
|SONGS Shield Ring Source: Picture from San Onofre Special Inspection Webinar, NRC Region IV, Arlington, TX, 11/08/18.
Click to enlarge.
The Nuclear Regulatory Commission (NRC) has released a preliminary report on the August 3rd accident where a cannister loaded with highly radioactive nuclear fuel rods became lodged at the top of its storage container 18 ft above its intended position during transfer from the cooling pool at San Onofre Nuclear Generating Station (SONGS).
The fuel cannister was lodged on the shield rings at the top of the storage container instead of passing through the rings had it been properly aligned.
Transfer of additional fuel cannisters was suspended a few days after the incident, and NRC staff conducted an onsite inspection September 10-14th. The recommendations arising from that inspection were recently released by the NRC.
In NRC jargon, the findings were:
• Two Preliminary Escalated Findings (Escalated means more serious violations)
– Failure to provide redundant drop protection
– Failure to report (incident reported by whistleblower)
• Three Preliminary Severity Level IV Violations (Level IV is the highest on the NRC scale)
– Corrective actions
• Management Oversight Weaknesses
The NRC Recommended corrective activities were:
• Increased training requirements
• Procedure enhancements
• Equipment enhancements
• Oversight improvements
The decision on whether or not Southern California Edison will be fined for these violations will not be made until NRC can evaluate the corrective measures.
The most controversial finding in the NRC report was that no radioactivity would have been released had the fuel canister fallen 18 feet. This assumption was immediately challenged by a number of experts, and the manufacturer of the canister, Holtec International, was unable to provide any test data on the thin stainless steel cannister integrity after such a fall while containing 45 tons of fuel rods. The transfer of more fuel rods remains on hold until the NRC approves the recommended corrective actions.