05000219/FIN-2008007-01
Finding | |
|---|---|
| Title | Drywell Sand Bed Water Intrusion, Drain Monitoring, and Coating Deficiency |
| Description | As noted in the detailed observations of this report, a number of issues were observed which Exelon placed into its corrective action program. The specific issues for further review include
(1) Exelon applied a strippable coating to the refuel cavity liner to prevent water intrusion into the gap between the drywell steel shell and the concrete shield wall. The strippable coating unexpectedly de-laminated, resulting in increased refuel cavity seal leakage. As a result, water entered the gap and subsequently flowed down the outside of the shell and into four sand bed bays. In addition, Exelon had established an administrative limit for cavity seal leakage that was higher than the actual leakage rate at which water intrusion into the gap occurred. (Sections 3.1 & 3.5) (2) While the reactor cavity was being filled, Exelon frequently monitored the cavity seal leakage by observing flow in the cavity trough drain line. Subsequently, Exelon determined that the trough drain line had been left isolated during a previous maintenance activity. As a result, cavity seal leakage had not been monitored as intended. (Section 3.2) (3) During the refueling outage, Exelon monitored for water leakage from the sand bed bay drains by checking poly bottles connected via tygon tubing and funnels to the sand bed drain lines. Exelon subsequently discovered that the poly bottle tubing was not connected to the drain lines for two sand bed bays. (Section 3.4) (4) Exelon identified four blisters on the epoxy coating in one sand bed bay. Exelon\'s evaluation to determine the cause of the blisters was still in-progress at the time this inspection was completed. In addition, a video recording from 2006 appeared to indicate that one of the blisters existed at that time, but was not identified during Exelon\'s 2006 visual inspection. (Section 3.9) The inspectors will review these issues in a future inspection to determine whether the individual issues are acceptable or constitute a CLB performance deficiency. The inspectors\' assessment will, in part, determine whether these items are consistent with design specifications and requirements, the conduct of operations, and whether appropriate administrative controls were utilized. (URI 05000219/2008007-01: Drywell Sand Bed Water Intrusion, Drain Monitoring, and Coating Deficiency) |
| Site: | Oyster Creek |
|---|---|
| Report | IR 05000219/2008007 Section 4OA5 |
| Date counted | Dec 31, 2008 (2008Q4) |
| Type: | URI: |
| cornerstone | No Cornerstone |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71003 |
| Inspectors (proximate) | J Kulp J Heinly J Richmond G Meyer M Modesj Richmondg Meyer M Modes J Kulp J Heinly |
| INPO aspect | |
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Finding - Oyster Creek - IR 05000219/2008007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Oyster Creek) @ 2008Q4
Self-Identified List (Oyster Creek)
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