05000293/LER-2018-005, Condition Prohibited by Technical Specifications Involving Standby Gas Treatment System Pneumatic Leakage Rate
| ML18260A084 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 09/12/2018 |
| From: | Miner P Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2.18.049 LER 2018-005-00 | |
| Download: ML18260A084 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 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)(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)(v), Loss of Safety Function 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)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 2932018005R00 - NRC Website | |
text
Letter Number 2.18.049 September 12, 2018 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Peter J. Miner Manager, Regulatory Assurance SUBJECT: Licensee Event Report 2018-005-00, Condition Prohibited by Technical Specifications Involving Standby Gas Treatment System Pneumatic Leakage Rate Pilgrim Nuclear Power Station Docket No. 50-293 Renewed License No. DPR-35
Dear Sir or Madam:
The enclosed Licensee Event Report 2018-005-00, Condition Prohibited by Technical Specifications Involving Standby Gas Treatment System Pneumatic Leakage Rate, is submitted in accordance with Title 1 O Code of Federal Regulations 50.73.
If you have any questions or require additional information, please contact me at (508) 830-7127.
There are no regulatory commitments contained in this letter.
PJM/rm : Licensee Event Report 2018-005-00, Condition Prohibited by Technical Specifications Involving Standby Gas Treatment System Pneumatic Leakage Rate
Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station cc:
Mr. David C. Lew Regional Administrator, Region I U.S. Nuclear Regulatory Commission 2100 Renaissance Boulevard, Suite 100 King of Prussia, PA 19406-2713 Mr. John Lamb, Senior Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8C2A Washington, DC 20555 NRC Senior Resident Inspector Pilgrim Nuclear Power Station Letter No. 2.18.049 Page 2 of 2 Letter Number 2.18.049 Licensee Event Report 2018-005-00, Condition Prohibited by Technical Specifications Involving Standby Gas Treatment System Pneumatic Leakage Rate (3 Pages)
SNRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017) htt12://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3l) the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
.PAGE Pilgrim Nuclear Power Station 05000-293 1 OF3
- 14. TITLE Condition Prohibited by Technical Specifications Involving Standby Gas Treatment System Pneumatic Leakage Rate
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR REV MONTH DAY YEAR N/A NUMBER NO.
N/A 07 17 2018 2018
- - 005
- - 00 09 12 2018 FACILITY NAME DOCKET NUMBER N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: Check all that applv)
N D 20.2201 (b)
D 20.2203(a)(3)(i)
D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A)
D 20.2201 (ct)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1 l D 20.2203(a)(4)
D so.73(a)(2)(iii)
D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 50.36(c)(1)(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
D 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(v)(A)
D 73.71 (a)(4)
D 20.2203(a)(2)(iii)
D so.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71 (a)(s) 100 D 20.2203(a)(2)(iv)
D so.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.77(a)(1)
D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(vi)
[8J 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(ii)
D 50.73(a)(2)(i)(C) 0 OTHER Specify in Abstract below or in NRG Form 366A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT rELEPHONE NUMBER (Include Area Code)
JMr. Peter J. Miner - Regulatory Assurance Manager
~08-830-7127 CAUSE SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TOEPIX X
BH y
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR D YES (ff yes, complete 15. EXPECTED SUBMISSION DATE)
[8'.J NO SUBMISSION DATE V\\BSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On July 17, 2018, with the Reactor in the Run Mode at approximately 100 percent power, it was determined
~hrough review of current and historical data that pneumatic leakage in the system used to operate dampers caused Train 'B' of the Standby Gas Treatment System (SGTS) to be made inoperable. Subsequent review determined that the condition existed for a period of time longer than allowed by Technical Specifications. This has been determined to be a reportable condition involving the SGTS in accordance with Title 1 O Code of Federal Regulations 50. 73( a) (2) (i) (B).
~ failure modes analysis was used to identify potential pneumatic air leakage paths and specific locations within the SGTS. Field work included leak checks, replacement of solenoid operated valves, repair of a damper actuator, and post-work testing of the system. SGTS Train 'B' was functioning properly but had a reduced mission time based on the as-found pneumatic system leakage rate. SGTS Train 'A' was operable during the period of time SGTS Train 'B' was inoperable.
This event had no impact on the health and/or safety of the public.
BACKGROUND SEQUENTIAL NUMBER
- - 005 REV NO.
- - 00 The Pilgrim Nuclear Power Station (PNPS) Standby Gas Treatment System (SGTS) is part of the Secondary Containment System (SCS) and addresses the SGTS air filtration trains, including the ducting, the exhaust ans, the dampers, and the various filtration media. The SCS is designed, in conjunction with other engineered safeguards and nuclear safety systems, to limit the release of radioactive material during normal plant operations within the limits of Title 1 O Code of Federal Regulations (CFR) Part 20, Standards for Protection Against Radiation, and to limit the release of radioactive material so that off-site dose from a postulated design basis accident will be below the guideline values in 1 O CFR Part 100, Reactor Site Criteria.
Upon receipt of an initiation signal, both SGTS fans start, heaters in both trains energize, and the dampers in both trains are aligned for service. The system can also be started manually from the control room. Each train's suction and discharge dampers are pneumatic; their motive power is supplied from a bank of air accumulators which, in turn, are charged from high pressure air bottles. SGTS Train 'A' isolation dampers fail open on loss of power and/or supply air, while the SGTS Train 'B' dampers fail closed.
EVENT DESCRIPTION
On July 17, 2018, while performing procedure 2.2.50, Standby Gas Treatment, Attachment 5, the leak rate in
~he pneumatic system was found to be greater than allowed in order to maintain SGTS Train 'B' operable for its 30-day mission time. At 1345 hours0.0156 days <br />0.374 hours <br />0.00222 weeks <br />5.117725e-4 months <br />, Limiting Condition for Operation (LCO) Action Statement (AS) 3/4.7.B.1.c was entered. The TS requires the inoperable train be made operable within seven days or reactor shutdown shall be initiated and the reactor shall be in cold shutdown within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The LCO AS was exited on Uuly 24, 2018, at 0628 hours0.00727 days <br />0.174 hours <br />0.00104 weeks <br />2.38954e-4 months <br /> when the condition was corrected. SGTS Train 'B' was functioning properly but had a reduced mission time based on the as-found pneumatic system leakage rate. Subsequent review of historical data indicated that the leak rate in the pneumatic system exceeded the allowable rate on July 2, 2018, at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />. Therefore, the seven day LCO AS was exceeded on July 9, 2018, at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />. The inoperability of SGTS Train 'B' for greater than the Allowed Outage Time (AOT) is a condition prohibited by TS.
CAUSE OF THE EVENT
The cause of the event was exceeding the design limit for pneumatic leakage in the system used to operate SGTS dampers and failure to establish methods to ensure degraded leakage rates were identified.
CORRECTIVE ACTIONS
A failure modes analysis was used to identify potential pneumatic air leakage paths and specific locations within the SGTS. Investigation identified two leaking solenoid valves: SV-L-62, SBGT Train 'B' inlet damper and SV-L-67, SBGT Train 'A' inlet damper. Subsequent investigation and field testing identified that damper AO-N-99 was also contributing to the leakage. Field work included leak checks, replacement of solenoid operated Page 2 of 3 (04-2017)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
, the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER YEAR Pilgrim Nuclear Power Station 05000- 293 2018
~alves, repair of a damper actuator, and post-maintenance testing of the system.
SEQUENTIAL NUMBER
- - 005 REV NO.
- - 00 Procedure 2.2.50, Standby Gas Treatment, was revised to record pneumatic system leakage rate upon charging the accumulators to have a real time check of system leakage with direction to initiate appropriate actions if leakage exceeds the allowable rate.
SAFETY CONSEQUENCES
SGTS Train 'B' was functioning properly but had a reduced mission time based on the as-found pneumatic system leakage rate. SGTS Train 'A' isolation dampers fail open on loss of power and/or pneumatic air, while
~he SGTS Train 'B' dampers fail closed. SGTS Train 'A' was operable at the time, so the SCS function was preserved.
lnoperability of SGTS Train 'B' had no impact on other required plant systems. SGTS does not contribute measurably to either the Core Damage Frequency or Large Early Release Frequency risk.
n-here were no consequences to the safety of the general public, nuclear safety, industrial safety, or radiological safety due to this event.
REPORT ABILITY One Train of SGTS made inoperable for a period of time greater than the AOT is a reportable condition in accordance with 1 O CFR 50.73(a)(2)(i)(B).
PREVIOUS EVENTS
~ review of PNPS Licensee Event Reports issued in the past three years was completed. The review focused on LERs that involved SGTS events, and in particular in-service failures. None were identified.
REFERENCES CR-PNP-2018-05919 CR-PNP-2018-05946 CR-PNP-2018-06103 Page 3 of 3