05000388/LER-2007-001, Regarding U2 Secondary Containment Bypass Leakage Exceeded
| ML071420048 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 05/08/2007 |
| From: | Saccone R Susquehanna |
| To: | Document Control Desk, Plant Licensing Branch III-2 |
| References | |
| PLA-6190 LER 07-001-00 | |
| Download: ML071420048 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded |
| 3882007001R00 - NRC Website | |
text
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Saccone Vice President - Nuclear Operations 1"
PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3959 Fax 570.542-1504 msaccone@pplweb.com PP MAY n 8 2007 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OPI-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-388/2007-001-00 PLA-6190 Docket 50-388 Attached is Licensee Event Report 50-388/2007-001-00. This event was determined to be reportable per 10 CFR 50.73(a)(2)(ii)(A) in that the secondary containment bypass leakage limit for Unit 2 was exceeded during regularly scheduled Local Leak Rate Testing.
There were no actual consequences to the health and safety of the public as a result of this event.
No new regulatory commitments have been created through issuance of this report.
Robert A.Saccone Vice President - Nuclear Operations Attachment cc:
Mr. A. J. Blarney, NRC Sr. Resident Inspector Mr. R. V. Guzman, NRC Project Manager Mr. R. R. Janati, DEP/BRP Mr. R. Osborne, Allegheny Electric
NRC FORM
)
U.S. NUCLEAR REGULATORY APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 the NRC may not conduct I or sponsor, and a person Is not required to respond to, the Information collection.
- 1. FACIMTY NAME Susquehanna Steam Electric Station - Unit 2
- 2. DOCKET NUMBER
- 3. PAGE 05000388 1 OF3
- 4. TITLE U2 Secondary Containment Bypass Leakage Exceeded
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACIUTIES INVOLVED MSEQUENTLIAL REV FACIUTY NAME DOCKET NUMBER MONTH DAY YEAR YEAR I NUMBER I No.
MONTH DAY YEAR050 FACIUTY NAME DOCKET NUMBER 03 09 2007 2007 001 00 05 08 2007 05000
- 9. OPERATING MODE
- 11. TI-S REPORTIS SUBMITTED PURSUANTTOTI.E REQUIREMENTS OF 10 CFR§: (Check el that epp/y) 5 [3 20.2201(b) 03 20.2203(aX3)(i)
[
50.73(aX2XIXC) 03 50.73(aX2Xvii)
- 10. POWER LEVEL
[] 20.2201(d) 03 20.2203(aX3)(ii) 0 50.73(aX2XiiXA) 0 50.73(aX2XviiiXA) o[ 20.2203(aX1)
[0 20.2203(aX4)
E3 50.73(aX2XiiXB)
[0 50.73(aX2XviiiXB) 0%
[ 20.2203(aX2)()
[0 50.36(cXIXiXA) 0l 50.73(aX2Xiii) 03 50.73(aX2XixXA) o3 20.2203(aX2)(d)
[0 50.36(cX1XIiXA) 03 50.73(aX2XivXA) 03 50.73(aX2Xx) o 202203(aX2Xiii) 0 50.36(cX2) 0 50.73(aX2XvXA)
[0 73.71(aX4) o 20.2203(aX2Xiv)
[0 50.46(aX3)ii) 0 50.73(aX2XvXB)
[0 73.71(aX5) o3 20.2203(aX2Xv) 03 50.73(aX2)(iXA) 0 50.73(aX2XvXC)
[0 OTHER Voluntary Report o3 20.2203(aX2Xv0) 0 50.73(aX2XiXB) 03 50.73(aX2XvXD)
Specify in Abstract below or In (ifmoe, is mqukW, use adcbalcopies of NRC Form 36WM)
EVENT DESCRIPTION
On March 9, 2007 at 1345 hours0.0156 days <br />0.374 hours <br />0.00222 weeks <br />5.117725e-4 months <br />, with Susquehanna Unit 2 in Mode 5 (Refueling) at 0% power, it was determined that the as-found minimum pathway Secondary Containment Bypass Leakage (SCBL) Technical Specification (TS) limit had been exceeded during regularly scheduled Local Leakage Rate Testing (LLRT). The TS SCBL limit is 9 scfh (4247 sccm). At the time the limit was surpassed, the station was testing the Unit 2 'A' Residual Heat Removal (EIIS Code: BO)
Containment Spray penetration. Despite work history that suggested leak rate failures at this penetration were not usually attributable to the isolation valve being tested (HV251 F01 6A) but were often caused by a leaking test boundary valve (HV251F021A), PPL lubricated and stroked the tested isolation valve before boundary valve repairs could be made.
This action required PPL to accept the higher than desired as-found LLRT results. Analysis has concluded that the boundary valve was, in fact, primarily responsible for the unsatisfactory LLRT results and that the event was caused by PPL's failure to rework the boundary valve and perform a second as-found leak rate test.
Total bypass leakage was determined to be 5892 sccm at the completion of the outage leak rate testing effort. The as-left SCBL total was reduced to 953 sccm following maintenance. This is well below the TS limit of 4247 sccm.
IOCFR50 Appendix J minimum pathway limits were not exceeded.
CAUSE OF EVENT
The higher than desired leak rate experienced at the Unit 2 'A' Residual Heat Removal Containment Spray penetration was primarily attributable to a leaking test boundary valve. The event was caused by PPL's failure to rework the boundary valve and perform a second as-found leak rate test.
ANALYSIS I SAFETY SIGNIFICANCE This event was determined to be reportable in accordance with 1 OCFR50.73(a)(2)(ii)(A) in that the total as-found minimum pathway leakage rate exceeded the TS limit.
Actual Consequences:
The purpose of primary containment (EllS Code: NH) isolation valves is to limit fission product release durng and following postulated Design Basis Accidents. The SCBL TS value is established to limit the release of radioactive materials outside of secondary containment to ensure offsite and main control room doses remain within regulatory limits. No event occurred during the SCBL testing (Mode 5) or during any other plant condition over the past operating cycle to challenge 1 OCFR1 00 or 1 OCFR50, Appendix A, GDC 19 dose limits. As such, there were no actual safety consequences resulting from this event.
Potential Consequences:
Analysis has concluded that, during a postulated design basis accident, any increase in dose related to the elevated SCBL leak rate would not have exceeded either 10CFRIOO or 10CFR50, Appendix A, GDC 19 dose limits.
('novr space Is requie4 use addionaf copies of NRC Form 3668)
CORRECTIVE ACTIONS
Following valve maintenance activities, as-left SCBL values meet established TS limitations.
Corrective Actions are planned to more dearly identify those leak rate tests that contribute to SCBL in procedures, maintenance wrkx plans, and station schedules. Troubleshooting plans will be pre-staged for SCBL related LLRT activities.
ADDITIONAL INFORMATION
Failed ComDonents Information:
Component HV251F016A; 12 inch globe valve Model:
W8522332B Manufacturer: Anchor Darling Valve Co.
Past Similar Events:
LER 96-002-00, Docket No. 387/License No. NPF-14 LER 96-011-00, Docket No. 387/License No. NPF-14 LER 99-002-00, Docket No. 388/License No. NPF-22 LER 01-003-00, Docket No. 388/License No. NPF-22