ML050950236
| ML050950236 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 03/30/2005 |
| From: | Lagergren W Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| EA-05-036 IR-05-007 | |
| Download: ML050950236 (3) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 William R. Lagergren, Jr.
Site Vice President, Watts Bar Nuclear Plant MAR 3 0 2005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
In the Matter of the Tennessee Valley Authority
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Docket No. 50-390 WATTS BAR NUCLEAR PLANT (WBN) - RESPONSE TO NRC INSPECTION REPORT 50-390/2005-007 PRELIMINARY WHITE FINDING (EA-05-036)
Reference:
Letter from Victor McCree, Director, Division of Reactor Projects, to K. W. Singer, TVA Chief Nuclear Officer and Executive Vice President, NRC Inspection Report No. 05000390/2005007; Preliminary White Finding; Watts Bar Nuclear Plant, dated March 2, 2005.
TVA has reviewed NRC's letter dated March 2, 2005 (reference) and appreciates the opportunity to offer its perspective on the facts and assumptions used by NRC to arrive at the preliminary white finding and its significance. TVA agrees with the characterization of the preliminary white finding.
The Essential Raw Cooling Water backup cooling line to the 1A Centrifugal Charging Pump oil cooler that was the subject of the finding has been cleared of silt and is being monitored on a quarterly basis to ensure it remains available.
The reason for not selecting this line for increased monitoring frequency has been traced to an incorrect corrective action step in 2002. That action did not identify the line for inclusion in a new monitoring procedure for portions of the system which do not normally see flow.
Accordingly, when subsequent actions were taken to increase the frequency of monitoring using this procedure to address instances of silting, this single line was not included.
PrIfed on recId aper
I U.S. Nuclear Regulatory Commission Page 2 MAR 3 0 2005 In addition to determining the proximate cause of this finding, TVA is also looking at the wider organizational and programmatic causes of the condition. WBN's attention to raw water systems had been actively focused on a concurrent macrofouling problem that treated silting as a contributing condition. Because the silt monitoring program seemed to be working by identifying silt deposits before they impacted component functions, no special effort to re-verify the completeness of the monitoring program was considered. The trend of silting issues has since been evaluated under a significant corrective action document and actions are being implemented to ensure that silt deposits do not prevent plant components from functioning.
The referenced inspection report also commented on significant differences between the TVA and NRC risk models for initiating event frequency for this issue. Actions were previously underway to upgrade WBN's PSA Revision 2 model and the existing draft Revision 3 model was confirmed to more closely match NRC's risk profile. The Revision 3 model is scheduled to be issued for use by June of this year.
TVA recognizes its important obligation to ensure the WBN Corrective Action Program vigorously identifies trends and corrects plant problems before they have an opportunity to impact plant equipment performance. Senior management will ensure the corrective actions associated with this finding will strengthen this important cross-cutting program.
If you have any questions regarding this response, please contact me at (423) 365-8767.
-a U.S. Nuclear Regulatory Commission Page 2 MAR 3 0 2005 cc:
NRC Resident Inspector Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 Mr. D. V. Pickett, Project Manager U.S. Nuclear Regulatory Commission MS 08G9 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303