05000335/LER-2001-009
| Docket Number | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3352001009R00 - NRC Website | |
DOCKET
Description of the Event
On September 4, 2001, St. Lucie Unit 1 was in Mode 1 operation at 100 percent reactor power. LI-1103, the pressurizer cold calibrated level instrument [EIIS:IP:LI], was taken out of service on October 12, 2001 to replace a power supply [EIIS:IP:RJX]. On October 13, 2001, Operations initiated a condition report to evaluate if action statement 1 of Table 3.3-11 of Technical Specification 3.3.3.8, "Accident Monitoring Instrumentation," should have been entered earlier due to increasing degradation of LI-1103. Based on a review of LI-1103's instrument history, St. Lucie determined that the instrument should have been declared out of service during the surveillance performed on September 4, 2001.
Cause of the Event
The degradation of LI-1103 was due to a failing power supply. The cause of this event, failing to declare LI-1103 out of service due to increasing degradation, was personnel error with inadequate surveillance procedure requirements contributing to the event. The Conduct of Operations procedure (0010120) and OP-1-0010125A, Surveillance Data Sheets, provide guidance on declaring instruments inoperable when readings taken during channel checks cannot establish proper operation of the instrument.
St. Lucie Unit 1 Technical Specification (TS) Table 3.3-11 states that the total number of channels of pressurizer water level is three and the minimum number of channels required to be operable is one. � In order to ensure compliance with this TS, the pressurizer level instruments are channel checked monthly. However, the criteria for performing an adequate channel check for LI-1103 were unclear; no guidance was given for the use of another similar instrument to channel check nor was there an established quantitative measure of acceptable operation.
Analysis of the Event
This event is reportable pursuant to 10 CFR 50.73(a)(2)(i)(B) as operation of the facility in a manner prohibited by TS. The amount of time operation with LI-1103 in a failed condition exceeded the 30 day allowed outage time (AOT) permitted by TS Table 3.3-11, Action 1.
Analysis of Safety Significance Accident monitoring instrumentation should meet Regulatory Guide 1.97 environmental qualification and qualify requirements to assure that these instruments are operable post accident. NUREG-1432, Standard Technical Specifications (STS) for CE Plants, only requires two total channels of pressurizer level instrumentation. Unlike the STS, the TS for St. Lucie Unit 1 required three total channels of pressurizer level instrumentation. Pressurizer level instruments LI-1110X and LI-1110Y are environmentally qualified and are credited to satisfy Regulatory Guide 1.97 instrumentation requirements. The third channel, LI-1103, is not environmentally qualified, is not powered by Class lE power and is not credited to satisfy regulatory Guide 1.97 requirements. Based on the above, FPL submitted a change to the TS to align the pressurizer level instrumentation requirements with NUREG-1432. This change was included in the license amendment submitted on April 18, 2001 by FPL letter L-2001-078. The NRC approved this change in St. Lucie Unit 1 TS amendment 177 on October 18, 2001.
Pressurizer level instrument LI-1103 was never intended to be qualified as post accident monitoring instrumentation. This TS error was corrected by a license amendment that was subsequently approved by the NRC. During this event qualified instruments provided accident monitoring instrumentation for pressurizer level.
Therefore, this event had no impact on the health and safety of the public.
Corrective Actions
1. The erroneous TS requirements for LI-1103 were removed by approval of St. Lucie Unit 1 TS amendment number 177.
2. The faulty power supply replacement was completed under work order 31016388 on October 23, 2001.
3. Operations personnel involved in this event have been held accountable.
4. The issue was discussed during Operator Requalification Training to demonstrate error prevention.
5. Procedure enhancements for OP-1-0010125A are planned to: a) improve Data Sheet 26 with references to ensure that degraded instruments identified during the performance of DS-26 are processed properly, and b) expected parameters to applicable portions of DS-26 will be added.
Additional Information
FPL recognized and submitted the proposed license amendment to correct the TS requirements for LI-1103 well before the event date of September 4, 2001. However, the discovery date and reportability "clock" for this event occurred on October 13, 2001. Even though the TS amendment was approved on October 18, 2001, 10 CFR 50.73 and Revision 1 to NUREG 1022 requires reporting of events where the operation or condition was prohibited at the time of discovery of the event.
Failed Components Identified Component: L Power Supply Manufacturer: Lamda Model No.: L LCS-B-24 Similar Events None