05000387/LER-2012-003, Regarding Unit 1 Secondary Containment Bypass Leakage Exceeded
| ML12157A371 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 06/05/2012 |
| From: | Helsel J Susquehanna |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PLA-6862 LER 12-003-00 | |
| Download: ML12157A371 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 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)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 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)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3872012003R00 - NRC Website | |
text
Jeffrey M. Helsel Nuclear Plant Manager U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OPl-17 Washington, DC 20555 PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3510 Fax 570.542.1504 jmhelsel@pplweb.com SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2012-003-00 LICENSE NO. NPF-14 PLA-6862 Docket No 50-387 Attached is Licensee Event Report (LER) 50-387/2012-003-00. This event was determined to be reportable in accordance with 10 CFR 50.73(a)(2)(ii)(A) as a degraded or unanalyzed condition. This event is also reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) for a condition prohibited by Technical Specifications. During the Unit 1 17th Refueling and Inspection Outage, the as-found minimum pathway Secondary Containment Bypass Leakage Technical Specification limit was exceeded during the regularly scheduled Local Leak Rate Testing.
There were no actual consequences to the health and safety of the public as a result of these events.
No commitments were identified in this submittal.
Attachment: LER 50-387/2012-003-000 Copy:
NRC Region I Mr. P. W. Finney, NRC Sr. Resident Inspector Mr. R. R. Janati, DEP/BRP Ms. C. J. Sanders, NRC Project Manager
NRC FORM 366 (10-2010}
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 LICENSEE EVENT REPORT (LER)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME (See reverse for required number of digits/characters for each block)
Susquehanna Steam Electric Station Unit 1
- 4. TITLE Unit 1 Secondary Containment Bypass Leakage Exceeded
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 2. DOCKET NUMBER 05000387
- 3. PAGE 1 OF 3
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH FACILITY NAME DOCKET NUMBER NUMBER NO.
YEAR 05000 DAY 04 06 2012 2012 - 003 -
00 06 05 2012 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
D 20.2201(b)
D 20.2203(a)(3)(i)
D 50.73(a)(2)(i)(C)
D 50.73(a)(2)(vii) 5 D 20.2201 (d)
D 20.2203(a)(3)(ii) t8l 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A)
D 20.2203(a)(1)
D 20.2203(a)(4)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B) 1---------10 20.2203(a)(2)(i)
D 50.36(c)(1)(i)(A)
D 50.73(a)(2)(iii)
D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(ii)
D 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50.73(a)(2)(v)(A)
D 73.71{a)(4)
D 20.2203(a)(2)(iv).
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(B)
D 73.71(a)(5)
D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(C)
D OTHER 0%
D 20.2203(a)(2)(vi)
[8] 50.73(a)(2)(i)(B)
D 50.73(a)(2)(v)(D)
Specify in Abstract below or'in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER Facility Name Brenda W. O'Rourke, Senior Engineer-Nuclear Regulatory Affairs
CAUSE
SYSTEM COMPONENT X
BD ISV MANU-FACTURER A391 REPORTABLE TO EPIX y
- 14. SUPPLEMENTAL REPORT EXPECTED 0 YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
CAUSE
[8] NO ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
Telephone Number (Include Area Code}
(570) 542-1791 MANU-SYSTEM COMPONENT FACTURER
- 15. EXPECTED SUBMISSION DATE MONTH REPORTABLE TO EPIX DAY YEAR On April 6, 2012, during the Susquehanna Unit 1 1 ih Refueling and Inspection Outage, it was determined that the as-found minimum pathway Secondary Containment Bypass Leakage (SCBL) Technical Specification (TS) limit was exceeded during the regularly scheduled Local Leak Rate Testing (LLRT). At the time the limit was exceeded, a LLRT was being performed on the Unit 1 'A' Feedwater Line Penetration X-9A. The tested containment isolation valve 141818A (FW LINE A ISO VLV TO RX) was leaking 2,855 standard cubic centimeters per minute (seem). When the 2,855 seem leakage through the 141818A valve was added to the combined as-found minimum pathway SCBL calculation, it equaled 7,185 seem [15.224 standard cubic feet per hour (scfh)]. This total as-found minimum pathway leakage exceeded the TS limit of 7,079 seem (15 scfh).
TS Surveillance Requirement 3.6.1.3.11 states, "Verify the combined leakage rate for all secondary containment bypass leakage paths is less than or equal to 15 scfh when pressurized to greater than or equal to P a*" In accordance with 10 CFR 50.72(b)(3)(ii)(A), on April 6, 2012, ENS notification(# 47812) was made to the NRC for a degraded or unanalyzed condition.
This condition is also reportable under 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by TSs because the total as-found minimum pathway SCBL leakage rate of 7,185 seem exceeded the TS limit of 7,079 seem.
The apparent cause of the excessive leakage through the 141818A valve was due to a galled disc stud and minor seat wear.
The valve's disc stud was repaired and the soft seat was replaced. As a result, the as-left valve leakage was reduced from 2,855 seem to 415 seem. A modification was completed during the Unit 1 17RIO which replaced the containment spray penetration isolation valves for containment penetrations X-39A/B and X-17 with smaller isolation valves in the Condensate Transfer and Residual Heat Removal to Liquid Radwaste lines. This modification reduced the SCBL total by approximately 50 percent.
There were no actual adverse consequences to the health and safety of the public since the dose consequences from the additional leakage would not have exceeded regulatory limits.
NRC FORM 366 (10-2010)
CONDITION PRIOR TO THE EVENT Unit 1 - Mode 5, 0 percent Rated Thermal Power
EVENT DESCRIPTION
I REVISION NUMBER 00
- 3. PAGE 20F3 On April 6, 2012, during the Susquehanna Unit 1 1 ih Refueling and Inspection Outage (RIO), it was determined that the as-found minimum pathway Secondary Containment Bypass Leakage (SCBL)
Technical Specification (TS) limit was exceeded during the regularly scheduled Local Leak Rate Testing (LLRT). At the time the limit was exceeded, a LLRT was being performed on the Unit 1 'A' Feedwater Line Penetration X-9A. The tested containment isolation valve 141818A (FW LINE A ISO VLV TO RX) was leaking 2,855 standard cubic centimeters per minute (seem). When the 2,855 seem leakage through the 141818A valve was added to the combined as-found minimum pathway SCBL calculation, it equaled 7,185 seem [15.224 standard cubic feet per hour (scfh)]. This total as-found minimum pathway leakage exceeded the TS limit of 7,079 seem (15 scfh).
TS Surveillance Requirement 3.6.1.3.11 states, "Verify the combined leakage rate for all secondary containment bypass leakage paths is less than or equal to 15 scfh when pressurized to greater than or equal to Pa." In accordance with 10 CFR 50.72(b)(3)(ii)(A), on April6, 2012, ENS notification(# 47812) was made to the NRC for a degraded or unanalyzed condition. This condition is also reportable under 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by TSs because the total as-found minimum pathway SCBL leakage rate of 7,185 seem exceeded the TS limit of 7,079 seem.
CAUSE OF THE EVENT
The apparent cause of the excessive leakage through the 141818A valve was due to a galled disc stud and minor seat wear. This excessive leakage, in combination with the carryover leakage from the containment spray penetration X-39A/B and X-17 valves (3,893 seem) during the Unit 1 16th RIO, resulted in the TS SCBL limit being exceeded.
ANALYSIS I SAFETY SIGNIFICANCE Actual Consequences The purpose of the primary containment isolation valves is to limit fission product release during 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 NRC regulatory limits. No event occurred during the SCBL testing or during any other plant condition over the past operating cycle that would have challenged the regulatory limits. As such, this event did not impact the health and safety of the public.
Potential Consequences Analysis has concluded that during a postulated design basis accident, the increase in dose related to the elevated SCBL leaks rate would not have exceeded NRC regulatory limits. U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
- 1. FACILITY NAME LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 2. DOCKET
- 6. LER NUMBER YEAR NUMBER Susquehanna Steam Electric Station Unit 1 05000387 I
SEQUENTIAL 2012
- - 003-
CORRECTIVE ACTIONS
Completed Actions I
REVISION NUMBER 00
- 3. PAGE 30F3 Maintenance was performed on the Unit 1 'A' Feedwater Line Penetration X-9A valve 141818A. The disc stud was repaired and the soft seat was replaced. This reduced the as-left valve leakage from 2,855 seem to 415 seem.
A modification was completed during the current Unit 1 17RIO which replaced the containment isolation valves for Containment Spray penetrations X-39A/B and X-17, as SCBL barriers, with smaller isolation valves in the Condensate Transfer and Residual Heat Removal (RHR) to Liquid Radwaste lines. This modification reduced the Containment Spray penetration X-398 leakage from 4,515 seem to 3,893 seem.
Planned Corrective Actions
A Unit 2 modification to replace the containment isolation valves for Containment Spray penetrations X-39A/B and X-17 as SCBL barriers with smaller isolation valves in the Condensate Transfer and RHR to Liquid Radwaste lines i~ planned for the next Unit 2 RIO.
With the Unit 1 modification to replace the containment isolation valves for containment spray complete as noted above, (although not included in the SCBL calculation for Unit 1 17RIO) the next step is to address the performance of the feedwater check valves. Condition Reports are in the SSES corrective action program to address these valves which could have future impact on SCBL.
ADDITIONAL INFORMATION
Failed Component Information:
Component: 141818A; 24-inch Advanseal check valve Model: None Manufacturer: Anchor Darling Valve Co.
Previous Similar Events
LER 2010-001-00, Docket No. 3871 License No. NPF-14 LER 2007-001-00, Docket No. 388 I License No. NPF-22 LER 2001-003-00, Docket No. 388 I License No. NPF-22 LER 1999-002-00, Docket No. 388 I License No. NPF-22 LER 1996-011-00, Docket No. 387 I License No. NPF-14