05000247/LER-2004-003
| Docket Number | |
| Event date: | 10-20-2004 |
|---|---|
| Report date: | 12-17-2004 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2472004003R00 - NRC Website | |
Note: � The Energy Industry Identification System Codes are identified within the brackets ().
DESCRIPTION OF EVENT
On October 20, 2004, at approximately 1920 hours0.0222 days <br />0.533 hours <br />0.00317 weeks <br />7.3056e-4 months <br />, while at about 90.7 percent daily average steady state reactor power during coast-down, Chemistry determined that the set point of vapor containment (VC) {NH} noble gas gaseous radiation monitor {MON} 42 (R-42) was not in compliance with the Technical Specification (TS) 3.3.6 allowable value of the time was 1.2E-5 micro-curies/cc, a factor of 1000 difference. This set point has been used since well before the implementation of TS amendment 238 (conversion of TS based on NUREG 1431 and implementation of NRC Generic Letter 89-01, removing effluent regulation to the Offsite Dose Calculation Manual (ODCM)) on December 19, 2003 and has been consistently above the background by more than a factor of three. Condition Report 1P2-2004-5027 was initiated to document this event. Corrective action was taken to reset the R-42 set point to meet the TS allowable value with the term "background" synonymous with the monitor reading during periods of minimal or no primary leakage.
R-42 is a process radiation monitor that monitors containment atmosphere for gaseous activity and initiates closure of the containment purge supply valves FCV-1170 and 1171 {FCV}, the containment purge exhaust valves FCV-1172 and 1173, and the containment pressure relief valves PCV-1190, 1191, and 1192 {PCV) on a high radiation signal (Updated Final Safety Analysis Report (UFSAR) Sections 11 and 5.2). When the plant is on line, these valves are normally closed, with the exception of the pressure relief valves which are periodically opened for short time periods during a pressure relief.
The TS Section 3.3.6 allowable value (AV) for R-42 (i.e., implementation of TS amendment 238 on December 19, 2003. Prior to this amendment, there were no AVs in the TS for the gaseous radiation monitor (R-42) used for leakage detection (TS 3.1.F) and containment isolation of purge and pressure relief valves (TS Table 3.5-4). When the TS were revised in amendment 238 the default set point of NUREG 1431 (4= 2 times background) was adopted with some modification. This failed to recognize that existing set point was based on the requirements of 10 CFR 20 release requirements (an environmental TS requirement).
The set points for the Victoreen Digital Radiation Monitoring System (DRMS) {IL}, of which R-42 is a channel, are controlled by an Operator Aid that is posted on the DRMS console in the Central Control Room (CCR) {NA}. The set point change process for R-42 has been informal with responsibility variable. At various times it has been under the control of the System Engineer, Radiation Protection and Chemistry, and Operations Support. The last Operator Aid was signed by the Operations Support Supervisor. Approved set point changes are implemented in the field by Operators or by Instrumentation and Control Technicians. At the time of this event, surveillance test PT-M82 verified the set points in the operator aid. The R-42 high alarm set point of 1.2E-2 micro-curies/cc has been used since at least 1997 and was based on a back-calculation for maximum concentration in the containment under typical release rates to ensure compliance with 10CFR20 release rate limits. The use of this set point since at least 1997 was determined from a review of completed copies of surveillance test PT-M82 since historical copies of the Operator Aid could not be located. This set point was not changed by the project to convert TS to the NUREG 1431 TS (ITS Project). A review concluded that the ITS Project team as well as the reviewers did not identify that the current set point was based on 10 CFR 20 criteria or identify the need to change the set point when adopting the new value.
The ITS project was managed and run by a Project Manager reporting to the Licensing Manager. Preparation of submittals, coordinating reviews, and update of plant documents were among the responsibilities of the project, which was composed of supplemental personnel. Review records for TS Section 3.3.6 could not be located, therefore, it is not clear whether the actual reviewer(s) made an error by not verifying the set point or a process problem caused the error.
The submittal states that the R-42 Allowable Value was determined using engineering judgment and that the addition of the AV was a more restrictive change. The ITS Project team was required to validate the inclusion of more restrictive changes into procedures which did not occur in this case. The set point for R-42 was not entered into PT- M82 and the operator aid was not revised. Whether the cause of this error by the ITS project team was human error or process error could not be determined because of a lack of records and personnel are no longer working on site. The errors by reviewers and the ITS team could be human error (i.e., a failure to meet the expectation of capturing a more restrictive AV in a procedure and verifying the same) or a process control inadequacy (i.e., the process and procedures were inadequate to establish clear guidance and responsibilities). The existing ineffective control process for radiation monitor set points during the period of time the TS change was prepared, reviewed, and approved indicates that process error was the most likely cause of this event.
CAUSE OF EVENT
The apparent cause of the event was a process control inadequacy by the ITS Project team and by TS section reviewer(s) who did not identify that the original set point was based on 10 CFR 20 limits or that the operator aid containing the set point required a change to reflect the new set point.
CORRECTIVE ACTIONS
The following corrective actions have been or will be performed under the corrective action program:
- The set point on R-42 was reset.
- The Operator Aid 2-OA-04-004 was revised to reflect the requirements of TS 3.3.6.
- A review was conducted of radiation monitor set points in TS, Technical Requirements Manual and Operational Dose Control Manual to verify that the proper set points / allowable values are incorporated.
- Formalizing and improving the process for controlling radiation monitor set points has been initiated in corrective actions.
EVENT ANALYSIS
This event is reportable under 10 CFR 50.73(a)(2)(i)(B). The licensee shall report any operation or condition which was prohibited by the plant TS. This event meets the criteria since the required set point of TS 3.3.6 for R-42 of three (3) times background was not met. R-42 was set at 1.2E-2 micro-curies/cc, more than 1000 times greater than the background at the time of 1.2E-5 micro-curies/cc. This condition has existed since implementation of TS amendment 238 on December 19, 2003, a period of approximately 10 months. The set point was corrected.
SIMILAR EVENTS
IPEC Licensee Event Reports (LER) for the past two years were reviewed and three TS violations on Unit 2 were identified. These events, LERs 2002-05 and 06 and LER 2003-02, were not caused by process control issues.
SAFETY SIGNIFICANCE
This event had no significant effect on the health and safety of the public. There was no actual event requiring operation of the R-42 to isolate the containment ventilation system {VA}. The set point used in R-42 prior to this condition being identified is adequate to meet the Containment Ventilation isolation function for an accident.' The assumed release of the source term is very rapid and the set point is well below the source term used for evaluating accident conditions (FSAR section 14). Additionally, downstream Plant Vent Monitor R-44 provides the same auto closure function.