05000374/LER-2002-001, Re Transient Increases in Unit 2 Unidentified Leakage Due to Clogged Drywell Floor Drain Sump Cover
| ML021480495 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 05/13/2002 |
| From: | Rommel J, Schiavoni M Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 02-001-00 | |
| Download: ML021480495 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3742002001R00 - NRC Website | |
text
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Exelon Generation Company, LLC WvVv. exeloncoTp con Nuclear LaSalle County Station 2601 North 21'Road Marseilles, IL 61341-975 7 May 13, 2002 10 CFR 50.73 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Unit 2 Facility Operating License No. NPF-18 NRC Docket No. 50-374
Subject:
Licensee Event Report In accordance with 10 CFR 50.73(a)(2)(i)(B), Exelon Generation Company, (EGC), LLC, is submitting Licensee Event Report Number 02-001-00, Docket No. 050-374.
Should you have any questions concerning this letter, please contact Mr. Glen T. Kaegi, Regulatory Assurance Manager, at (815) 415-2800.
Respectfully, Mark A. Schiavoni Plant Manager LaSalle County Station Attachment: Licensee Event Report cc:
Regional Administrator - NRC Region IlIl NRC Senior Resident Inspector - LaSalle County Station
F
Abstract
l400 spaces, i.e.,
approximately titeen single-space LypewtLUILw 1111i)
On March 16,
- 2002, the calculated unidentified leakage on Unit 2 reached 3.0 gpm, which exceeded the value calculated the previous day by more than 2.0 gpm.
Technical Specification (TS) 3.4.5.d limits the increase in unidentified leakage within the previous 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period to less than or equal to 2.0 gpm.
The increase in unidentified leakage was transient, and returned to normal values.
Troubleshooting indicated that debris collected on the drywell floor from previous maintenance activities had clogged the drywell floor drain.
This debris restricted flow through the floor drain, which created a hold up of water on the drywell floor.
This rendered the leakage detection system incapable of identifying increases in unidentified leakage of 2.0 gpm within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Agitation of the debris from normal equipment shifts allowed the water to drain into the sump at an increased rate.
The cause was determined to be inadequate post-outage cleaning of the drywell floor.
The drain covers and the drywell floor were cleaned.
Periodic maintenance activities will be created to clean and inspect the drywell floor following refueling outages.
The safety significance of the event was minor, since the unidentified leakage was less than TS limits, and redundant means to detect reactor coolant leakage were available.
NRC FORM 366 (7-2001)
(If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)
G.
COMPONENT FAILURE DATA
Since no component failure occurred, this section is not applicable.