05000255/LER-2006-006, Regarding Inoperable Containment Due to Containment Air Cooler Through-Wall Flaw
| ML063610189 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/15/2006 |
| From: | Harden P Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 06-006-00 | |
| Download: ML063610189 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(viii) |
| 2552006006R00 - NRC Website | |
text
Committed to Nuclear Excell Palisades Nuclear Plant Operated by Nuclear Management Company, LLC December 15, 2006 10 CFR 50.73(a)(2)(i)(A) 10 CFR 50.73(a)(2)(v)(C)
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Plant Docket 50-255 License No. DPR-20 Licensee Event Report 06-006, Inoperable Containment Due to Containment Air Cooler Through-Wall Flaw Licensee Event Report (LER)06-006 is enclosed. The LER describes the discovery of a through-wall flaw in a containment air cooler tube and the resultant effect on the containment boundary. This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(A) and 10 CFR 50.73(a)(2)(v)(C).
Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.
Paul A. Harden Site Vice President, Palisades Nuclear Plant Nuclear Management Company, LLC Enclosure (1)
CC Administrator, Region III, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC 27780 Blue Star Memorial Highway
- Covert, Michigan 49043-9530 Telephone: 269.764.2000
ENCLOSURE1 LER 06-006, Inoperable Containment Due to Containment Air Cooler Through-Wall Flaw 3 Pages Follow
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 6-30-2007 (6-2004)
Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and fed back to industry.
LICENSEE EVENT REPORT (LER)
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FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE (3)
Palisades Nuclear Plant 05000-255 1
of 3
TITLE (4)
Inoperable Containment Due to Containment Air Cooler Through-Wall Flaw EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MO DAY YEAR YEAR NUMBER NO MO DAY YEAR 11 01 2006 2006
-- 006 00 12 15 2006 FACILITY NAME DOCKETNUMBER OPERATING 1
THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR (Check all that apply) (11)
MODE (9) 20.2201 (b) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(ix)(A)
POWER 100 20.2201 (d) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(x)
LEVEL (10) 20.2203(a)(1) 50.36(c)(1 )(i)(A) 50.73(a)(2)(iv)(A) 73.71 (a)(4) 20.2203(a)(2)(i) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71 (a)(5) 20.2203(a)(2)(ii) 50.36(c)(2) 50.73(a)(2)(v)(B)
OTHER 20.2203(a)(2)(iii) 50.46(a)(3)(ii)
X 50.73(a)(2)(v)(C)
Specify in Abstract below or in 20.2203(a)(2)(iv)
X 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D)..
20.2203(a)(2)(v) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(C) 50.73(a)(2)(viii)(A)
S.....
20.2203(a)(3)(i) 50.73(a)(2)(ii)(A )
50.73(a)(2)(viii)(B )
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER (Include Area Code)
Daniel G. Malone (269) 764-2463 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
MANU-REPORTABLE MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX
CAUSE
SYSTEM COMPONENT FA CTURER TO EPIX SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED MONTH DAY YEAR YES (If yes, complete EXPECTED SUBMISSION DATE).
X NO DATE (15)U ABSTRACT On November 1, 2006, with the plant in Model, a small service water leak (approximately 0.4 gallons per minute) was identified in VHX-4 containment air cooler (CAC). Although the specific location of the through-wall flaw could not be verified due to physical constraints, the leak is assumed to be from a pin-hole in a single cooling coil tube.
The CAC cooling coil tubing is part of the containment boundary and is required to be structurally sound to ensure that post accident containment leakage will not exceed allowable leakage.
Therefore, Technical Specification (TS) Limiting Condition For Operation (LCO) 3.6.1, "Containment,"
is applicable for any through-wall defects noted in CAC cooling coil tubing. Since it was not possible to characterize the flaw and verify the structural integrity of the tube for post-accident conditions over the CAC's mission time, the plant was taken to Mode 3 in accordance with TS LCO 3.6.1.B.1.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(A) as the completion of a shutdown required by plant Technical Specifications and 10 CFR 50.73(a)(2)(v)(C) as a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2 LER NUMBER (6)
PAGE (3)
SEQUENTIAL REVISION YEAR NUMBER NUMBER 2 of 3 Palisades Nuclear Plant 05000-255 2006 006 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
EVENT DESCRIPTION
On November 1, 2006, with the plant in Model, a small service water [BI] leak (approximately 0.4 gallons per minute) was identified in VHX-4 containment air cooler (CAC) [CLR;BK]. The specific location of the through-wall flaw could not be physically verified, as the leak location was determined to be from the opposite side of the tube sheet. However, the leak is assumed to be from a pin-hole in a single cooling coil tube, similar to previous pin-hole leaks which have occurred in the cleanable-bend area of the cooling coil, on the visible side of the tube sheet.
Since VHX-4 has no safety-related cooling function, Technical Specification (TS) Limiting Condition For Operation (LCO) 3.6.6, "Containment Cooling Systems" was not affected. However, the CAC cooling coil tubing is also a part of the containment [NH] boundary, and is required to be structurally sound to ensure that post accident containment leakage will not exceed allowable leakage (La).
Therefore, TS LCO 3.6.1, "Containment," is applicable for any through-wall defects noted in CAC cooling coil tubing.
Although analysis showed that the identified leak size would not challenge La, it was not possible to characterize the flaw and verify the structural integrity of the tube for post-accident conditions over the CAC's mission time. Therefore, in accordance with TS LCO 3.6.1.B.1, the plant was taken to Mode 3.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(A) as the completion of a shutdown required by plant Technical Specifications and 10 CFR 50.73(a)(2)(v)(C) as a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
CAUSE OF THE EVENT
The probable cause of the through-wall flaw is loss of wall thickness due to flow induced erosion.
CORRECTIVE ACTIONS
The affected cooling coil was isolated by installing blanks on its inlet and outlet flanges. The VHX-4 CAC cooling coils are currently scheduled to be replaced during the Fall 2007 refueling outage.
SAFETY SIGNIFICANCE
The safety significance of this occurrence is considered to be minimal. For a worst case failure of a single CAC cooling coil tube, analysis has determined that all on-site and off-site dose limits would continue to be met for the bounding postulated post-accident scenario.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2 LER NUMBER (6)
PAGE (3)
YEAR I
SEQUENTIAL REVISION NUMBER NUMBER 3 of 3 Palisades Nuclear Plant 05000-255 2006 006 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
PREVIOUS SIMILAR EVENTS
Licensee Event Report 05-006, "Inoperable Containment Due to Containment Air Cooler Through-Wall Flaw"