05000269/LER-2008-001, Gas Void Found in High Pressure Injection System Suction Piping
| ML083230051 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/12/2008 |
| From: | Baxter D Duke Energy Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 08-001-00 | |
| Download: ML083230051 (10) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2692008001R00 - NRC Website | |
text
Duke DAVE BAXTER Vice President E~nergy.
Oconee Nuclear Station Duke Energy Corporation ON01 VP17800 Rochester Highway Seneca, SC 29672 864-885-4460 864-885-4208 tax dabaxter@dukeenergy. corn November 12, 2008 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555
Subject:
Oconee Nuclear Station Docket Nos.
50-269 Licensee Event Report 269/2008-01, Revision 0 Problem Investigation Process No.: 0-08-5600 Gentlemen:
Attached is voluntary Licensee Event Report 269/2008-01, Revision 0, regarding a void (gas bubble) found in the High Pressure Injection (HPI) System suction piping.
Analysis concluded that only one HPI pump would have been potentially rendered inoperable by the void, therefore the remaining train of HPI would have performed the safety function. Based on guidance in NUREG 1022, the time of discovery has been used as the initiation of the event due to absence of firm evidence to indicate when the void was formed.
As a result, the HPI System was not inoperable for a period of time longer than allowed by Technical Specifications.
Therefore this event is not considered reportable per 10 CFR 50.73 (a) (2) (i) (B) as operation in a condition prohibited by Technical Specifications or per 10 CFR 50.73 (a) (2) (v) as a condition which could have caused a loss of safety function.
- However, Duke Energy recognizes the regulatory interest in this issue as it relates to Generic Letter (GL) 2008-01, and is therefore submitting this voluntary report. Based on Duke's evaluation, the duration of the event was very short and had minimal risk significance.
There are no regulatory commitments contained in this report.
Corrective actions provided in Duke Energy's response to GL 2008-01 (letter dated October 13, 2008) are considered adequate to address this issue.
www. duke-energy. com
Document Control Desk Date: November 12, 2008 Page 2 Any questions regarding the content of this report should be directed to Graham Davenport at 864-885-3044.
Very truly yours, Dave Baxter, Vice President Oconee Nuclear Site Attachment cc:
Mr. Luis Reyes Administrator, Region II U.S. Nuclear Regulatory Commission 61 Forsyth Street, S.
W.,
Suite 23T85 Atlanta, GA 30303 Mr.
L.
N. Olshan Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C.
20555 Mr.
Andy Hutto NRC Senior Resident Inspector Oconee Nuclear Station INPO (Word File via E-mail)
Abstract
On 09/13/2008, while Oconee Unit 1 was operating in Mode 1 at 100% rated
- power, an examination being performed in response to Generic Letter (GL) 2008-01 detected a gas bubble (void) in the suction piping to the High Pressure Injection (HPI) suction header.
At 13:46 hours, Engineering completed a calculation of the void volume and initiated a Problem Investigation Process report.
At 15:12 hours, Engineering and Operations concluded that the void could render the 1A HPI pump and 1A HPI train inoperable.
Operations declared 1A HPI pump and 1A HPI train out of service and entered Technical Specification (TS) 3.5.2, Conditions A and C.
The line was vented, and, at 16:43 Operations declared the pump and train Operable and exited the TS conditions.
Additional examinations confirmed that the equivalent locations on the Unit 1B HPI train and on Units 2 and 3 did not contain voids.
No specific source or cause could be found for the void.
Duke Energy responded to GL 2008-01 by letter dated 10/13/2008 and committed to actions which are expected to permanently resolve this issue.
This event is considered to have minimal significance with respect to the health and safety of the public.
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 (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) does not have data to support pump operability under the void conditions predicted by the analysis.
Per guidance issued by the Nuclear Energy Institute (NEI) in NEI 99-02, Regulatory Assessment Performance Indicator Guideline, revision 5, it is appropriate to assume the time of discovery when calculating the impact of this event on the Mitigating System Performance Index.
Based on this assumption, the duration of the event was very short and had minimal risk significance and resulted in no impact on the health and safety of the public.
ADDITIONAL INFORMATION
Licensee Event Report 269/2006-03, revision 1, dated 05/29/2008, discussed inoperability of LPI pumps due to foreign material in the suction piping from the Reactor Building Emergency Sump lines.
This was a somewhat similar event in that LPI is also an ECCS system and operability of the suction flow path was affected.
It is not considered a recurring event due to different causes for the events.
Therewere no releases of radioactive materials, radiation exposures or personnel injuries associated with this event.
No equipment actually failed in association with this event.
Therefore, this event is not considered reportable under the Equipment Performance and Information Exchange (EPIX) program.
NRC FORM 366 (7-2001)