05000382/LER-2001-001
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3822001001R00 - NRC Website | |
REPORTABLE OCCURRENCE
On January 11, 2001, it was discovered that a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> channel check surveillance for the Pressurizer [AB-PZR] Pressure Narrow Range, Technical Specification 4.3.1.1 Table 4.3-1 Item (4) (TS 4.3.1.1(4)), was not properly completed. This surveillance log entry for TS 4.3.1.1(4) contained a notation indicating that the Core Protection Calculator (CPC) [JC-CPU] used to perform the channel check was inoperable. This channel of the high pressure reactor trip should have been declared inoperable, TS 3.3.1 for this function entered, and the bistable placed into bypass. These actions were not taken. The appropriate Technical Specification actions were not entered, resulting in a condition prohibited by the plant's Technical Specification. Research into the event identified two other performances of TS 4.3.1.1(4), which were inadequately performed.
INITIAL CONDITIONS
The plant was operating in Mode 1 at 100% power at the time the missed surveillances occurred. CPC Channel "D" was inoperable during these instances.
EVENT DESCRIPTION
On January 11, 2001, it was discovered that a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> channel check surveillance for the Pressurizer Pressure Narrow Range, TS 4.3.1.1(4), was not properly completed. Operations uses OP-903-001, 'Technical Specification Surveillance Logs,- to complete the TS Surveillances on shift. Attachment 11.1, "Modes 1-4 TS Surveillance Logs," has log entry fields for three different blocks of time. These time blocks are 0400-1200, 1200-2000, and 2000-0400. The surveillance log entry for the January 8, 2001 Pressurizer Pressure Narrow Range Channel D 0400-1200 field contained a notation and no pressure reading. The notation indicated that the CPC used to perform the surveillance per OP-903-001 was inoperable. Upon discovery of the incorrect surveillance, the Pressurizer Pressure Narrow Range Channel D was declared inoperable and TS 3.3.1 was entered.
Research into the event identified that two other performances of surveillance for TS 4.3.1.1(4) were performed incorrectly. These instances occurred on the January 10, 2001 TS Surveillance logs for the 1200- 2000 and 2000-0400 log entries. In all of three instances discovered, the log entry was left blank with a notation indicating that the associated CPC Channel was inoperable. The inoperability of the CPC only affects the ability to perform the channel check surveillance, both from the CPC and the plant monitoring computer.
NRC FORM 3156A (1-2001
CAUSAL FACTORS
The root cause of this event was determined to be change management, where the appropriate procedure was not properly revised. There were two contributing causes. The first was personnel work practices, where implementing documents were directly referenced, but they were not followed correctly. The second was corrective action, where a required corrective action was not issued.
CORRECTIVE ACTIONS
This event has been placed into our corrective action program along with the corrective actions. In summary, some of the corrective actions are:
- Informed Licensed Operators of the issues associated with this event and of the error trap in OP-903-001 to aid in the prevention of recurrence until the procedure is revised;
- Conducted a debrief of the involved crews to reinforce the significance of the error, the proper method for using the data in the TS logs of OP-903-001, and to reinforce the standard of performance expected in Operations;
- Revise OP-903-001 to incorporate the alternate indications allowed for recording the channel check of Pressurizer Pressure narrow range;
- Conduct training with Operations licensed personnel on TS issues to include how TS logs satisfy the various TS Surveillances.
SAFETY SIGNIFICANCE
This event involves the failure to either perform the required channel check or enter TS 3.3.1 for the Pressurizer pressure high trip function for channel D. The events that took place for this error started when CPC 0 failed. This prevented the channel check reading from being obtained per OP-903-001.
Through an event debrief, it was discovered that different members of the involved crews observed the required parameter using the control room board indicator on CP-7. The crews did not connect that the failure to record the Pressurizer narrow range pressure constituted a failure to complete the channel check required by TS 4.3.1.1. It was the missed channel check that rendered the high pressure reactor trip administratively inoperable for channel D. The channel checks required by TS 4.3.1.1 had been completed satisfactorily before the event, and the channel D high pressure reactor trip displayed no indications of any types of failures before and after the missed log readings.
The bases for TS 3.3.1 states that the operability of independent systems is required to provide the overall reliability, redundancy, and diversity assumed available in the facility design for the protection and mitigation of accident and transient conditions. The failure of CPC Channel D had no impact on the availability and function of the high pressure reactor trip for channel D. Neither the reliability, redundancy, nor diversity of any train of Plant Protection System (PPS) were challenged due to missing the channel check reading.
Based on the absence of a problem with PPS channel D other than the missed reading, combined with the crews observation of proper Pressurizer narrow range pressure on channel D, there are no safety concerns related to this event due to the missed channel check.
TS Surveillance 4.2.8, which verifies that the Pressurizer narrow range pressure remains in the range assumed in the safety analysis, only requires 1 operable Plant Monitoring Computer or CPC reading. CPC A, B, and C were operable throughout this period and the surveillance was properly satisfied on each of the days the channel check was missed. Since the surveillance was satisfied during the period of discussion, there is no safety concern related to TS 3.2.8 due to missing the PPS channel check surveillance.
This event is not considered a Safety System Functional Failure (55FF).
SIMILAR EVENTS
CR-WF3-2000-1547 discussed a condition where the plant changed from mode 2 to mode 1 without completing the proper TS Surveillances prior to mode change. This event was reported to the NRC under verification was not performed CR-WF3-2000-1515 discussed a condition where the plant changed from mode 5 to mode 4 without meeting the required Limiting Conditions for Operation prior to changing modes. This event was reported to the NRC under LER 00-012-00. The cause of this event was that the mode change checklist did not provide an organized method of verifying the configuration of control panels required for mode changes.
CR-WF3-1999-1150 identified that the control room board indicators contained more uncertainty than one of the TS Surveillances allowed. The apparent cause was that the technical and safety reviews of OP-903-001 failed to verify that the specified instrument met the accuracy requirement and that the engineering judgement used for the application of instrument uncertainty to Pressurizer Pressure limits was incorrect.
CR-WF3-1998-0802 discussed a condition prohibited by TS, which was not performing a channel check TS Surveillance within its specified interval and not properly entering the required TS actions. This event was reported to the NRC under LER-98-012-00. Its cause was personnel error in that Operations personnel incorrectly concluded that a parameter no longer required tracking via a computer point.
ADDITIONAL INFORMATION
Energy Industry Identification System (EDS) codes are identified in the text within brackets [ 3.
FACILITY NAME (1) � DOCKET (2) I � LER NUMBER (6) � PAGE (3) 01 - 001 - 00