05000352/LER-2005-004
| Limerick Generating Station | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3522005004R00 - NRC Website | |
Unit Conditions Prior to the Event Unit 1 was in Operational Condition (OPCON) 1 (Power Operation) on May 29, 2004 at approximately 94% power returning to 100% power from a control rod pattern adjustment and on September 11, 2004 at approximately 94% power returning to 100% poWer from a control rod pattern adjustment. There were no structures, systems.or.componentn.out_of.serviceihat contributed to this event.
Description of the Event
On September 20, 2005 General Electric issued a Part 21 report notification to the NRC.
The report identified an error in the GE-14 ATLAS critical power test results due to deformation of the Zircaloy spacers used in GE-14 and GE-12 fuel [ENS: AC].
An evaluation of Limerick Unit 1 operating history identified that a noncompliance with Technical Specification 3.2.3 Minimum Critical Power Ratio occurred on two occasions. The evaluation of Unit 2 determined that TS compliance was maintained during the current operating cycle.
On May 29, 2004, a control rod pattern adjustment was performed on Unit 1. The evaluation determined that a noncompliance with Technical Specification 3.2.3 occurred for approximately six hours. The peak Maximum Fraction of Limiting Critical Power Ratio (MFLCPR) value was 1.03.
On September 11, 2004, a control rod pattern adjustment was performed on Unit 1. The evaluation determined that a noncompliance with Technical Specification 3.2.3 occurred for approximately seven hours. The peak MFLCPR was 1.002.
This event involved periods of operation that were piohibited by Technical Speciiications.
Therefore, this LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(i)(B).
Analysis of the Event
There were no actual safety consequences associated with this event. The potential safety consequences of this event were minimal.
There was no adverse impact to the fuel and very low safety significance since no transient occurred during the times when MFLCPR exceeded 1.0; therefore no safety limit was challenged.
Cause of the Event
The event was caused by a deformation in the Zircaloy spacer during GE-14 ATLAS critical power testing. This deformation resulted in a non-conservative error in the test results.
Corrective Action Completed� -- An evaluation of Unit 1 and Unit 2 vulnerability to the Part 21 condition has been completed. No compensatory measures are required at this time.
To prevent a similar issue from occurring on Unit 2, an administrative limit was entering the portion of the operating cycle where the Part 21 issue is applicable.
Corrective Action Planned GE is currently reviewing previous cycles for Unit 1 and Unit 2, which GE will complete by December 31, 2005.
A new databank and coding will be installed in Unit 1 and Unit 2 3D Monicore. This action will be completed by March 31, 2006.
Previous Similar Occurrences There were no previous similar occurrences where noncompliance with a TS power distribution limit existed for a period that exceeded the TS action statement allowance for restoration.
_ Component data:
Cause: B (Design, Manufacturing, Construction/Installation) System: AC Reactor Core System Component: N/A Manufacturer: G080 General Electric Type: GE-14 Fuel Model: N/A Reportable to EPIX: No