05000306/LER-2005-001, Re Shutdown Required by Technical Specifications Due to Two Trains of Containment Cooling Inoperable
| ML051590105 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 05/27/2005 |
| From: | Solymossy J Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-PI-05-005 LER 05-001-00 | |
| Download: ML051590105 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3062005001R00 - NRC Website | |
text
NC PraiOe Island Nuclear Generating Plant CuOperated by Nuclar Management Company, LLC MAY 2 7 2005 L-PI-05-005 10 CFR 50.73 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Unit 2 Docket 50-306 License No. DPR-60 LER 2-05-01, Unit 2 Shutdown Required by Technical Specifications Due to Two Trains of Containment Cooling Inoperable The Licensee Event Report for this occurrence is attached. Notification of this event as required by 10 CFR 50.72(b)(2)(i) was made on March 30, 2005. Please contact us if you require additional information related to this event.
Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.
Zp M. Solymos V Site Vice President, irie land Nuclear Generating Plant Nuclear Management ompany, LLC Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC Glenn Wilson, State of Minnesota 1717 Wakonade Drive East
- Welch, Minnesota 55089-9642 Telephone: 651.388.1121
ENCLOSURE LICENSEE EVENT REPORT 2-05-01 4 pages follow
I NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 3150.0104 EXPIRES 6-30-2007 COMMISSION.
CMI2004)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE (3)
Prairie Island Nuclear Generating Plant Unit 2 05000 306 1 of 4 TITLE (4)
Unit 2 Shutdown Required by Technical Specifications Due to Two Trains of Containment Cooling Inoperable EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
MOQUEEAR YERI MO FACILITY NAME DOCKET NUMBER MO DAY YEAR YEA NUBE NO MO DAY YEAR 3 30 05 05
- - EQ IA I5 31FACILITY NAME DOCKET NUMBER OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check all that apply) (11)
MODE (9) 20.2201(b) 20.2203(a)(3)(ai) 50.73(a)(2)(ii)(B) 50.73(a)(2)(ix)(A)
POWER 20.2201 (d) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(x)
LEVEL (IO) l 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) 50.73(a)(2)(v)(C)
Specify in Abstract below or in 20.2203(a)(2)(iv) 50.73(a)(2)(1)(A) 50.73(a)(2)(v)(D) 20.2203(a)(2)(v)
X 50.73(a)(2)(T)(B) 50.73(a)(2)(vii) 20.2203(a)(2)(vi) 50.73(a)(2)(T)(C) 50.73(a)(2)(viii)(A) 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)
Jeff Kivi I
651.388.1121 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 SUBMISSION YES (If yes. complete EXPECTED SUBMISSION DATE).
X NO DATE (15) l l
l ABSTRACT On March 28, 2005 a Corrective Action Process (CAP) item identified potential non-code repairs had been made to 21, 22, and 23 Containment Fan Coil Units (CFCUs) since January 2005. The repair performed was an overlay described as filling a pinhole leak with brazing material in the copper tubing of the CFCU. This repair may not have removed the flaw and was not done in accordance with a code approved weld repair procedure.
An Operability Recommendation performed by Engineering examined the qualifications of the repair techniques utilized on previous Unit 2 CFCU leakage events and concluded that while the structural integrity could be assured the repair constituted a non-code repair. Temporary non-code repairs are not acceptable, per NRC Generic Letter 90-05, without prior NRC approval. This conclusion resulted in 3 of the 4 CFCUs, being declared inoperable and required Unit 2 to be shutdown per Technical Specifications until code repairs were completed.
Code repair of the 21, 22, and 23 CFCUs were completed on April 3, 2005.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET NUMBER (2 l i LER NUMBER (6)
PAGE (3)
SEQUENTIAL IREVISION Prairie Island Nuclear Generating'Plant Unit 2 05000306 lYEAR NUMBER NUMBER 2of4 05 01 0
TEXT (If more space Is required, use additional copies of NRC Form 366A) (17)
EVENT DESCRIPTION
On March 28, 2005 a Corrective Action Process (CAP) item identified potential non-code repairs had been made to 21, 22, and 23 Containment Fan Coil Units1 (CFCUs) since January 2005. The repair performed was an overlay described as filling a pinhole leak with brazing material in the copper tubing of the CFCU. This repair may not have removed the flaw and was not done in accordance with a code approved weld repair procedure. The initial operability evaluation concluded that the CFCUs remained operable.
Further evaluation, in the form of an Operability Recommendation performed by Engineering examined the qualifications of the repair techniques utilized on previous Unit 2 CFCU leakage events and concluded on March 30 that while the structural integrity could be assured the repair constituted a non-code repair. The CFCU tubes are American Society of Mechanical Engineers (ASME) Code Class 2. Temporary non-code repairs are not acceptable, per Nuclear Regulatory Commission (NRC) Generic Letter 90-05, without prior NRC approval. This conclusion resulted in 3 of the 4 CFCUs, being declared inoperable and required Unit 2 to be shutdown per Technical Specifications (TS) until code repairs were completed.
Code repair of the 21, 22, and 23 CFCUs were completed on April 3, 2005.
EVENT ANALYSIS
The containment cooling system is a closed system in containment. There are two trains with two CFCUs per train. Integrity of the tubes in the CFCUs is required for containment integrity. The CFCU tubes support two safety functions: (1) circulating cooling water for containment cooling in the event of a loss of coolant accident (LOCA) or main steam line break in containment, and (2) serving as a containment boundary during the first hours of a LOCA when containment pressure will exceed the pressure of the cooling water in the CFCUs.
TS 3.6.5, Containment Spray and Cooling Systems, allows one train of containment cooling to be inoperable. TS 3.6.1, Containment, requires that containment be operable. Containment and both trains of containment cooling were declared inoperable as a result of this condition and a Unit 2 shutdown was completed per TS 3.0.3 (since TS 3.6.5 does not have a condition for two trains of containment cooling inoperable) and TS 3.6.1. Thus, this shutdown is reportable per 10 CFR 50.73(a)(2)(i)(B).
1 (EIIS Component Identifier: FCU) 2 (EIIS System Identifier: BK)U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2 LER NUMBER (6 PAGE (3)
'~
n~nnn~n~ YEAR UENTIAL IREVSION Prairie Island Nuclear Generating Plant Unit 2 05000306 l
YE NUMBER NUMBER 3 of 4 05 01 0
TEXT (If more space Is required, use additional copies of NRC Forn 366A) (17)
Impact on Safety System Functional Failure Performance Indicator The CFCUs contain an air-to-water heat exchanger supplied with water from the cooling water system in order to remove containment heat. In this event, three of the CFCUs were determined to be inoperable due to non-code repairs of pinhole leaks that had not received prior approval from the NRC. There was no active leak at the time this condition was discovered and an engineering assessment concluded that structural integrity of the CFCUs was not lost. Therefore, this event did not result in loss of any safety function, thus,-this event is not reportable per 10 CFR 50.73(a)(2)(v)(C) as a Unit 2 Safety System Functional Failure (SSFF).
SAFETY SIGNIFICANCE
There were no active leaks occurring when this condition was discovered and the engineering assessment concluded that the non-code repairs would have maintained structural integrity. Based on this assessment, the health and safety of the public was not affected.
CAUSE
Nuclear Management Company, LLC, (NMC) conducted a root cause evaluation of this condition.
The root cause evaluation determined planners and technical reviewers lack of understanding led to the selection of a brazing procedure that was not qualified for the joint configuration that was used.
CORRECTIVE ACTION
Immediate:
- 1. Unit 2 was shutdown per Technical Specification 3.0.3.
Subsequent:
- 2. 21, 22, and 23 CFCUs were repaired per the ASME Code and returned to service. As noted in Licensee Event Report 2-04-01, Supplement 1, Unit 2 CFCU cooling coils have been replaced since this event occurred.
Planned:
- 3. The Root Cause Evaluation recommended a number of training actions to correct limitations of the knowledge of site personnel who would be involved in any potential future repairs.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2 LER NUMBER (6)
PAGE 3 Prairie Island Nuclear Generating Plant Unit 2 05000306 YEAR NSEUENTIAL MREVON 4 of 4 05 01 0
TEXT (If more space Is required. use additional copies of NRC Form 3664) (17)
PREVIOUS SIMILAR EVENTS
Licensee Event Report 2-04-01 was submitted pursuant to 10 CFR 50.73(a)(2)(i)(B) for a Technical Specification required shutdown that was a result of CFCU leaks.