05000335/LER-2010-001, Air Intrusion from 1A Containment Instrument Air Compressor Into Unit 1 Component Cooling Water (CCW) System
| ML101031100 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 04/05/2010 |
| From: | Richard Anderson Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2010-056 LER 10-001-00 | |
| Download: ML101031100 (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)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(iii) 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)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(ii) |
| 3352010001R00 - NRC Website | |
text
FPL Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 April 5, 2010 L-2010-056 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re: St. Lucie Unit 1 Docket No. 50-335 Reportable Event: 2010-001 Date of Event: February 04, 2010 Air Intrusion from IA Containment Instrument Air Compressor into Unit 1 Component Cooling Water (CCW) System The attached Licensee Event Report 2010-001 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
Very truly yours, Richard L. Anderson Site Vice President St. Lucie Plant RLA/dlc Attachment r~J tUL an FPL Group company
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/201(
(9-2007)
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. Send comments regarding burden estimate to the Records and FOIAIPrivacy Service Branch (T-5 LICENSEE EVENT REPORT (LER)
F52), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollectsgnrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-1 0202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE St. Lucie Unit 1
05000335 11 OF 4
- 4. TITLE Air Intrusion From 1A Containment Instrument Air Compressor Into Unit 1 Component Cooling 1.
YEAR I YEAR SEQUENTIA I NUMBER IFACILITY NAME 201012010 -
001 00 20.2201(b) 20.2201 (d) 20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(2)(ii) 20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(2)(v) 20.2203(a)(2)(vi)
El El El El El El El El El 20.2203(a)(3)(i) 20.2203(a)(3)(ii) 20.2203(a)(4) 50.36(c)(1)(i)(A) 50.36(c)(1)(ii)(A) 50.36(c)(2) 50.46(a)(3)(ii) 50.73(a)(2)(i)(A) 50.73(a)(2)(i)(B)
El El El El El El El 0
50.73(a)(2)(i)(C) 50.73(a)(2)(ii)(A) 50.73(a)(2)(ii)(B) 50.73(a)(2)(iii) 50.73(a)(2)(iv)(A) 50.73(a)(2)(v)(A) 50.73(a)(2)(v)(B) 50.73(a)(2)(v)(C) 50.73(a)(2)(v)(O)
E]
El El El El El El El 50.73(a)(2)(vii) 50.73(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50.73(a)(2)(ix)(A) 50.73(a)(2)(x) 73.71 (a)(4) 73.71 (a)(5)
OTHER Specify in Abstract below or in numerous points within the CCW system for which low flow alarms might have been received, no other flow alarms were logged from any other CCW system location.
Evaluation of the CCW system indicated that Operators detected and eliminated the source of the air ingress well in advance of the system becoming incapable of supporting normal power operation.
However, air intrusion of the amount in this event is an unanalyzed condition and review of operating alignments indicate that had a design basis accident (LOCA) occurred, assuming Operators did not isolate the air ingress source, continuous air ingress into the CCW system would result in the operability of the one available essential CCW header being indeterminate resulting in an unanalyzed condition which could have prevented the fulfillment of a safety function.
Consequently 10 CFR 50.73 (a) (2) (ii) and 10 CFR 50.73(a) (2) (v) require notification of the NRC via a License Event Report (LER).
Analysis of Safety Significance Air intrusion of the amount which occurred during the October 2008 event into the CCW system is an unanalyzed condition.
An Engineering evaluation concluded the Operators detected and eliminated the source of the air ingress well in advance of the CCW system becoming incapable of supporting normal power operation.
Assuming Operators do not isolate the air ingress source, this continuous air ingress into the CCW system under design basis accident conditions would have resulted in the operability of the CCW system being indeterminate.
The probability of a design basis accident such as a LOCA concurrent with an air intrusion event is smaller than that of a loss of CCW due to the short fault exposure times.
Corrective Actions
The corrective and supporting actions are entered into the Site Correction Action Program (CAP).
Any changes to the proposed actions will be managed under CAP.
- 1. Lesson plans for Licensed Operator and Non-Licensed Operators have been revised to include the RCE completed for this event as well as discussions on the recognition and mitigation of gas intrusion into plant cooling water systems resulting from operating experience within the Industry.
- 2.
Implement positive isolation between the containment IA compressor fill lines and CCW utilizing additional isolation capability.
- 3.
Revise Eng-QI 1.8 to include a design consideration to prevent creation of an interface between a gas subsystem and a fluid system whereby gas intrusion can occur either by component leakage or failure that could lead to a common mode failure of the fluid system in a future design.
Similar Events
This event is not considered a repeat event however, a similar event subsequently occurred on September 9, 2009, but appropriate actions were taken to address operability.
Numerous opportunities to learn from internal and external operating experience (OE) were missed so that the 2008 CCW air intrusion event was not prevented.
Missed opportunities resulting from Industry operating experience have been added to lesson plans for Licensed Operator and Non-Licensed Operator Initial and Continuing Training.
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