05000280/LER-2005-002
| Docket Numbersequential Revmonth Day Year Year Month Day Year Surry Power Station, Unit 2Number No. 05000 - 281 | |
| Event date: | 07-25-2005 |
|---|---|
| Report date: | 09-11-2005 |
| 2802005002R00 - NRC Website | |
1.0 DESCRIPTION OF THE EVENT Units 1 and 2 were operating at 100% on July 25, 2005, when control room annunciator 1-RMA-C4 [EIIS-IB] alarmed, indicating a problem with the effluent radiation monitors [EIIS-IL,MON]. The appropriate annunciator response and abnormal procedures were promptly performed and a low sample flow condition was identified for the gaseous vents system radiation monitor, 1-GW-RM-130-1 (normal range). As a result of this condition, 1-GW-RM-130-1 and 1-GW-RM-130-2 (high range) were declared inoperable at 23:30 and the preplanned alternate method of monitoring was initiated in accordance with Technical Specifications (TS) Table 3.7-6. An action statement was entered in accordance with TS Table 3.7-6, requiring restoration of the monitors within seven days or the submittal of a Special Report within 30 days.
Recent extreme weather conditions resulting in high dewpoint temperatures challenged the existing heat trace on the 1-GW-RM-130-1 skid during the weeks previous to this event. TS action statements were entered on several occasions but were not exceeded. Instrument and Controls (I&C) and Engineering personnel replaced components and optimized heat trace temperature control in an effort to reduce moisture accumulation and improve reliability of the system. In addition, aging and obsolescence issues have resulted in difficulty obtaining spare parts for these monitors. On July 27, 2005, additional heat trace was installed on the 1-GW-RM-130-1 skid. The system was returned to service on July 28, 2005 and the TS action statement was exited.
This Voluntary Special Report is being submitted pursuant to TS Table 3.7-6 since 1-GW-RM-130-1 experienced repetitive problems that challenged its operability over a period of several weeks.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS 1-GW-RM-130-1 and 1-GW-RM-130-2 are designed to monitor effluents that may be released from the process vent stack following an accident. When the subject monitors were declared inoperable, the preplanned alternate method of monitoring was initiated, utilizing process vent stack high range effluent monitor, 1-GW-RM-122. In addition, Health Physics personnel were notified that the monitors were out of service. Therefore, this event resulted in no safety consequences or significant implications and the health and safety of the public were not affected at any time.