05000397/LER-2014-004
| Columbia Generating Station | |
| Event date: | 1-4-2014 |
|---|---|
| Report date: | 10-09-2014 |
| 3972014004R00 - NRC Website | |
Plant Conditions
At the time of the event the plant was operating in Mode 1 at 100% power. This event documents an administrative issue with TS compliance, therefore no structures, systems, or components were inoperable that contributed to this event.
Event Description
On August 14, 2014 it was discovered that Columbia Generating Station's (Columbia) method of complying with Technical Specification (TS) Surveillance Requirement (SR) 3.7.1.1 for Ultimate Heat Sink (UHS) [BS] spray pond level was inadequate.
Columbia's UHS consists of two concrete spray ponds. These spray ponds provide suction and discharge points for the redundant pumping and spray facilities of the Service Water (SW) [Blj system. SW loop A draws water from pond A and discharges through a spray ring into pond B for heat dissipation. Similarly, SW loop B draws water from pond B and discharges through a spray ring into pond A. The water then returns to the initial pond through a siphon line. During operation with one SW pump running, a differential level develops between the ponds until flow through the siphon line equalizes with the running SW pump. The spray ponds remain with this differential level until the running pump is stopped and flow through the siphon line equalizes the spray pond levels. The ponds were licensed such that the combined water volume of the spray ponds is adequate to provide cooling water for 30 days of operation, assuming maximum evaporation and drift losses.
Prior to implementation of improved TS (ITS) in June of 1997, there were separate TS for SW and UHS. The UHS TS contained a SR to verify the UHS water level was within its limit of 432 ft 9 inches mean sea level at a frequency of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The operations surveillance procedure contained a note to take an arithmetic average of the spray pond levels if only one loop of SW was in operation. In March 1997, Columbia received license amendment 149 for ITS with a full implementation date of June 30, 1997. The ITS combined the SW and UHS into one TS. The UHS water level surveillance requirement was changed to require the level in each spray pond to be within the limit of 432 ft 9 inches. Due to the design of the spray ponds and SW system, it is difficult to meet this requirement in each pond when only one SW pump is in operation.
This discrepancy between the new TS SR and how it is implemented in operations surveillance procedures was identified in 1997 and license document changes were initiated to change the TS SR and the TS Bases to allow for an arithmetic average of the two ponds when a single pump is in operation. The TS Bases change was processed; however the TS SR change was not completed. The reason why the TS SR wasn't completed and submitted to the NRC for approval is undocumented and unknown.
Cause
The cause of this event Is that although it was recognized in 1997 that Columbia was out of verbatim compliance with TS SR 3.7.1.1. Columbia's licensing document change process in 1997 allowed for changes to the TS SR and TS Bases to be processed separately. This allowed the TS Bases change to be implemented while the TS SR change was never completed or approved by the NRC.
28158A R3 NRC FORM MA (01-2014) Columbia Generating Station YEAR Extent of Condition An extent of condition review determined that there have been multiple instances when SW would need to be declared inoperable based on spray pond level as it is common practice to operate individual service water pumps based on plant needs. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Limiting Conditions for Operation per TS 3.7.1 was exceeded on August 13, 2014 with additional occurrences since implementation of the ITS on June 30, 1997.
Immediate Corrective Action Once it was discovered that the operations procedure was not compliant with the TS SR all oncoming operations crews were briefed on the correct implementation of the TS SR. Guidance was also given to start both SW pumps if one is required to run. The operations surveillance procedure was also updated to remove the wording which allowed for the arithmetic average of the two ponds when a single pump is in operation.
Columbia has submitted a TS change to the NRC to allow verification that the average water level in the UHS spray ponds is within the limit. The licensing change process is being updated to ensure processing of TS SR changes with TS Bases changes if related.
Operating Experience & Previous Occurrences No previous occurrences have been found to have the same cause of a license amendment change not processed. One event reported under LER-12-004-02 was a failure to enter a TS action statement due to conflicting information between the associated TS Bases and the surveillance procedure. Corrective actions focused on operability determinations for equipment removed from service. It also included a focused self- assessment to review TS Bases and TS SRs. The self-assessment did not identify the discrepancy described in this LER, and therefore a re-review of the work performed by this individual is being completed to ensure no other discrepancies between TS SR, TS Bases and implementing procedures exist.
Further Corrective Actions A review of all TS Bases amendments was conducted to identify whether any other Licensing Document Changes were issued that introduced conflicts with the literal wording in the TS.
Assessment of Safety Consequences
There were no actual safety consequences associated with this event as during periods of SW single loop operation when one pond level was below TS minimum the actual inventory of the UHS was unaffected. The combined inventory between the two ponds remained above the licensed amount required to provide adequate cooling for 30 days of operation.
Energy Industry identification System (EDS) Information Energy Industry Identification System (EIIS) Information codes from IEEE Standards 805-1984 and 803-1983 are represented in brackets as [XX] and [XXX] throughout the body of the narrative.
28158A R3 NRC FORM 368A (01-2014)