05000261/LER-2003-001
| Docket Number | |
| Event date: | 02-24-2003 |
|---|---|
| Report date: | 04-24-2003 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2612003001R00 - NRC Website | |
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) H. B. Robinson Steam Electric Plant, Unit No. 2 05000261
I. DESCRIPTION OF EVENT
At 0000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> on February 24, 2003, with the unit operating at full power, Technical Specifications (TS) Limiting Condition for Operation (LCO) Applicability requirement 3.0.3 was entered based on failure to meet the required actions of TS LCO 3.1.7.
Upon discovery that the required actions of TS LCO 3.1.7 were not met, appropriate action was taken and the required actions were subsequently satisfied at 0043 hours4.976852e-4 days <br />0.0119 hours <br />7.109788e-5 weeks <br />1.63615e-5 months <br />.
The required action in effect at the time was associated with Condition A, "One ARPI [Analog Rod Position Indication] per group inoperable for one or more groups.
Required Action A.1 states, "Verify the position of the rods with inoperable position indicators by using the movable incore detectors*." The asterisk (*) refers to a footnote that states, "During Cycle 22, the position of Control Rod H-10, Shutdown Bank B, can be determined by verifying gripper coil parameters of the Control Rod Drive Mechanism have not changed state, until the repair of the indication system is completed." The completion time associated with Required Action A.1 is once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. The use of the alternative action described by the footnote was being employed to satisfy Required Action A.1 for Control Rod H-10, which had been previously declared inoperable due to erratic indication [System Identifier Code: JD - Reactor Power Control System].
At approximately 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on February 23, 2003, the Required Action A.1 had been satisfied as stated in the H. B. Robinson Steam Electric Plant (HBRSEP), Unit No. 2, control room shift log. The 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> entry on February 23, 2003, states, "Verified position of rod H-10 using gripper coil voltage. Chart recorder indicates no interruption of current to the stationary gripper coil and voltage is >0.185 VDC.
Current voltage is: 270. This satisfies the required actions for ITS [Improved Technical Specifications] 3.1.7 Condition A." Although it was not known at the time, it was later determined that the chart recorder had been inadvertently stopped when the operator performed the verification.
The next completion of Required Action A.1 was scheduled for 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />, in accordance with the "once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />" completion time. At approximately 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />, the operator went to the Rod Control Room to perform the observations for the required action. When the operator was performing the required observations, he noted markings on the chart recorder paper and assumed that another operator had already completed the check of the chart recorder. The operator did not look FACILITY NAME (1) PAGE (3) LER NUMBER (6 DOCKET NUMBER (2) closely enough to realize that the markings were his own from 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> that day and that the recorder was in the stopped (also called halted) condition.
The day-shift operator was relieved by the night-shift operator at approximately 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br />. The night-shift operator proceeded to perform the observations in the Rod Control Room at 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br />. He noticed that the recorder was on, but the paper had not advanced since approximately 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br />. The night-shift operator reported his findings to the Control Room Shift Supervisor, who dispatched the Shift Technical Advisor (STA) to the Rod Control Room. When the STA arrived (approximately 0010 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />), he noted that the chart recorder was halted. The STA pressed the HALT/RUN button on the recorder and the recorder paper began advancing.
The Control Room Log states that TS LCO 3.0.3 was entered at 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> due to failure to perform the applicable required actions (i.e., verification of rod position in accordance with Required Action A.1 or reduction of reactor power to that when an LCO is not met and the associated required actions are not met, the unit shall be placed in a mode or other specified condition in which the LCO is not applicable. TS LCO 3.0.3 further states that action shall be initiated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to place the unit, as applicable, in MODE 3 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />; MODE 4 within 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />; and, MODE 5 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />.
The Control Room Log also states that procedure SP-1505, "Determination of the H10 Rod Position Using the Movable Incore Detector System," was started at 0010 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />.
SP-1505 was completed at approximately 0043 hours4.976852e-4 days <br />0.0119 hours <br />7.109788e-5 weeks <br />1.63615e-5 months <br />. Completion of SP-1505 restored compliance with Required Action A.1 and allowed TS LCO 3.0.3 to be exited.
Operations personnel resumed the required observations once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> in accordance with LCO 3.1.7, Required Action A.1.
A condition report (number 85523) was initiated and the corrective action program significant adverse condition investigation has been completed. This reportable event and the associated significant adverse condition investigation was reviewed by the Plant Nuclear Safety Committee on April 2, 2003.
The failure to meet the required actions associated with TS LCO 3.1.7 is a condition prohibited by the plant's Technical Specifications. Therefore, this condition is reportable based on 10 CFR 50.73(a)(2)(i)(B), "Any operation or condition prohibited by the plant's Technical Specifications.
H. B. Robinson Steam Electric Plant, Unit No. 2 05000261 FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) H. B. Robinson Steam Electric Plant, Unit No. 2 05000261
II. CAUSE OF EVENT
The cause of the event was determined to be operator error. The day-shift operator responsible for performing Required Action A.1 failed to recognize that the recorder had been halted during the 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> observation and that this condition continued during the 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> observation. The cause and circumstances of this human performance error were investigated. Potential causal factors were considered, including distractions, hurried or rushed, schedule pressure, fatigue, fitness for duty, work environment, stress, and overconfidence. It was concluded that none of these factors directly contributed to the cause of this event.
The method being used for compliance with LCO 3.1.7, Required Action A.1, was based on an amendment to the HBRSEP, Unit No. 2, TS that had been approved by the NRC on February 13, 2003, by Amendment No. 197. This amendment approved the use of the alternative method for monitoring the position of Control Rod H-10 in lieu of using the movable incore detectors once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. The alternative method involves use of a chart recorder to monitor stationary gripper coil voltage. During the investigation of this event, the training materials associated with the implementation of the TS amendment were reviewed. The training was deemed to be sufficient, although it was noted that the training materials lacked details pertaining to the operation of the chart recorder. A corrective action was implemented to address this item.
The operator's conclusion that the chart recorder paper had already been reviewed and annotated for the 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> observation indicates that the operator knew the requirements that needed to be satisfied. The error occurred because the operator failed to validate and confirm the information observed. If the operator had appropriately identified at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> that the recorder was halted, TS compliance would have been maintained by simply performing SP-1505 at that time. The condition prohibited by the TS arose because the required action time for Required Actions A.1, A.2, and D.1 had elapsed. Together, Required Actions A.1, A.2, and D.1 effectively required the unit to be completion of LCO 3.1.7, Required Action A.1. The 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> time limit is based on 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> allowed to complete Required Action A.1, plus 25% of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> as allowed by TS Surveillance Requirement (SR) Applicability 3.0.2, and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to be in MODE 3 in accordance with Required Action D.1 for the required action and associated completion time not met.
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) H. B. Robinson Steam Electric Plant, Unit No. 2 05000261
III. ANALYSIS OF EVENT
LCO 3.1.7, Required Action A.1, establishes the appropriate compensating action and completion time for inoperability of an ARPI. If this action cannot be performed, Required Action A.2 allows the unit to be operated at no other compensating action. As stated in the bases for LCO 3.1.7, rod positions are monitored and controlled during power operation to ensure that the power distribution and reactivity limits defined by the design power peaking and shutdown margin are preserved. The bases for Required Action A.2 also states that reduction of thermal power to factors due to rod position.
The failure to meet these required actions within the associated completion times requires entry into Condition D of LCO 3.1.7, which states, "Required Action and associate Completion Time not met." Required Action D.1 states that the unit is to be in MODE 3 within a 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> completion time. Required Action D.1 can be exited when the unit reaches would be met. Therefore, the cumulative completion time to reduce power to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> from the successful completion of the Required Action A.1. The failure to meet the 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> time limit required entry into LCO Applicability 3.0.3. Completion of procedure SP-1505, which satisfied Required Action A.1, allowed LCO Applicability 3.0.3 to be exited, and the recurring completion time of "once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />" for Required Action A.1 was resumed.
LCO 3.1.7, Required Action A.1, was subsequently satisfied at 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 43 minutes after the last completion of that required action. This exceeded the 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> cumulative time limit for the reactor to be exceeded the allowed time to complete Required Action A.1 by 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. As stated in the license amendment request and associated NRC safety evaluation for the alternate position monitoring for H-10, a rod drop or misalignment would be detectable by the excore nuclear detectors. This provides assurance that if a malfunction associated with Control Rod H-10 had occurred, it would have been detected and appropriate actions taken at that time. Additionally, completion of SP-1505 at 0043 hours4.976852e-4 days <br />0.0119 hours <br />7.109788e-5 weeks <br />1.63615e-5 months <br /> confirmed that Control Rod H-10 had not moved from the required, fully withdrawn position. Therefore, safe operation of the plant was not affected by this event.
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) H. B. Robinson Steam Electric Plant, Unit No. 2 05000261
IV. CORRECTIVE ACTIONS
The corrective actions for this event that have been completed include the following:
— discussion of this event with each shift at turnover as an interim action, — a caution tag was placed on the chart recorder warning operators that opening the cover on the recorder will halt the recorder and that pressing the RUN/HALT button will restart the recorder after the cover is closed, — a night order (03-004) was issued, which clarifies the operation of the recorder, — a signoff was added to the auxiliary operator log for the review and proper operation of the chart recorder, and — additional training information was distributed to the operations crews that includes photographs of the recorder and specific details of the different displays.
V. ADDITIONAL INFORMATION
A. Failed Component Information:
There were no failed components associated with this event.
B. Previous Similar Events:
A review of recent (past 3 years) events at HBRSEP, Unit No. 2, for conditions prohibited by the TS was conducted. Licensee Event Report 2002-001-00 identifies steam generator safety valve inoperability discovered during testing that resulted in a condition prohibited by the TS. This event occurred due to equipment malfunction and is not relatable to this event. Licensee Event Report 2001-001-00 identifies a condition where a reactor core protection channel for detection of low reactor coolant system flow was found out-of-tolerance. This event was attributed to human error and lack of procedural guidance. The instrument and control system calibrations are performed by maintenance personnel and use different procedures than those used by the operators in conducting activities associated with the Control Rod H-10 verifications.
Therefore, the cause and corrective actions identified by Licensee Event Report 2001-001-00 would not have been expected to prevent the failure to meet the required actions for Control Rod H-10 ARPI inoperability.