05000461/LER-2013-007
| Clinton Power Station, Unit 1 | |
| Event date: | 10-28-2013 |
|---|---|
| Report date: | 12-27-2013 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4612013007R00 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
General Electric -- Boiling Water Reactor, 3473 Megawatts Thermal Rated Core Power Energy Industry Identification System (EllS) codes are identified in text as [XX].
EVENT IDENTIFICATION
Tech Spec Action Not Met for High Reactor Coolant Heatup Rate
A. Plant Operating Conditions Before the Event
Unit: 1 Event Date: 10/28/2013 Event Time: 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br /> CDT Mode: 2 Mode Name: STARTUP Reactor Power: 0 percent
B. DESCRIPTION OF EVENT
On 11/1/13 while reviewing logs (CPS 9000.06D001, Heatup/Cooldown, Inservice Leak and Hydrostatic Testing 30 Minute Temperature Logs), a Senior Reactor Operator (SRO) identified that a high reactor coolant heatup rate had occurred during the reactor startup following refueling outage C1 R14 on 10/28/13. At 1845 hours0.0214 days <br />0.513 hours <br />0.00305 weeks <br />7.020225e-4 months <br /> on 11/1/13, Operations management reviewed this event and concluded that the Actions of Technical Specification (TS) 3.4.11, "Reactor Coolant System Pressure/Temperature Limits" had not been properly applied.
On 10/28/13 a reactor startup was in progress with the plant in Mode 2. The reactor [RCT] achieved criticality at 2028 hours0.0235 days <br />0.563 hours <br />0.00335 weeks <br />7.71654e-4 months <br />. At 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br />, reactor coolant temperature was 156 degrees Fahrenheit (F) and the reactor was at the point of adding heat. As reactor pressure begins to rise, the Main Steam Isolation Valves (MSIVs) [ISV] are normally opened to align the Reactor Pressure Vessel [RPV] to the Main Condenser. At this point, the MSIVs could not be opened due to the Main Steam Lines being full of water following the RPV pressure test and RPV temperature and pressure continued to rise. Operators inserted a control rod to slow the heatup rate. At 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br />, the heatup logs showed reactor coolant temperature was about 267.3 degrees F and reactor coolant pressure was about 28 pounds per square inch (psi). This was a reactor coolant heatup rate greater than 100 degrees F per hour. Operators notified the Operations Shift Manager (SM) of the heatup trend and that the reactor coolant temperature had increased by about 111 degrees F over a one-hour period from 2030 to 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br />. The SM reviewed the log and noted that the RPV metal temperatures recorded on the log were still well under a rate of change of 100 degrees F per hour.
TS 3.4.11, Figure 3.4.11-3 for RPV heatup/cooldown limits states that the limit for the rate of heatup and cooldown of the reactor coolant limit is less than or equal to 100 degrees F per hour. Further, with the heatup limits not met, TS 3.4.11 Required Action A.1 requires restoration of parameter(s) to within limits within 30 minutes; and Required Action A.2 requires an assessment of the Reactor Coolant System to determine if it is acceptable for continued operation within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. During this event the reactor coolant heatup limit was exceeded without these TS actions being completed within their required associated Completion Time. The SM incorrectly implemented the TS requirement for RPV heatup by incorrectly applying the limitations for coolant temperature against metal temperature heatup rates and that reactor coolant temperatures are monitored for the purpose of ensuring that the metal temperature limits are not exceeded.
On the basis of exceeding the TS reactor coolant system (RCS) heatup rate and not completing the TS Required Actions within the Required Completion Time, this event is reportable under the provisions of 10 CFR 50.73(a)(2)(i)(B), as a condition that was prohibited by the plant's Technical Specifications. Issue Report No.1580123 was initiated to investigate this event.
C. CAUSE OF EVENT
During this event, the SM made an incorrect TS determination. The SM did not review the surveillance requirements contained within the procedure being performed nor did he reference TS or TS Bases documents as required by process. Additionally, no peer check was sought by an independent SRO as expected by management
D. SAFETY CONSEQUENCES
This event had no actual consequences. The heatup rate was terminated relatively quickly by the insertion of control rods and stabilization of pressure. Exelon Generation Company, LLC Engineering evaluated the recorded heatup rate and concluded it was bounded by pre-analyzed transients; therefore the structural integrity of the RPV was not adversely affected at any point during the RPV heatup.
E. CORRECTIVE ACTIONS
This was a personnel accountability issue where the SM on duty did not adequately review and apply TS.
The Operations department performed a stand down to review this event and to reinforce expectations associated with making TS reviews. Performance management of the individuals involved in this event has been completed and the SM has been removed from license duties. Additionally, this event will be presented to the License Operator Requalification Program and Shift Manager / Shift Technical Advisor curriculum review committees for incorporation into future training.
F. PREVIOUS OCCURRENCES
A review for previous occurrences did not identify similar events at Clinton Power Station.
G. COMPONENT FAILURE DATA
None