05000387/LER-2018-002, Loss of Secondary Containment Differential Pressure Following Surveillance Testing
| ML18150A633 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 05/30/2018 |
| From: | Berryman B Susquehanna, Talen Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PLA-7707 LER 2018-002-00 | |
| Download: ML18150A633 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3872018002R00 - NRC Website | |
text
MAY 3 0 2018 Brad Berryman Site Vice President U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Susquehanna Nuclear, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.2904 Fax 570.542.1504 Brad.Berryman@TalenEnergy.com SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387(388)/2018-002-00 UNIT 1 LICENSE NO. NPF-14 UNIT 2 LICENSE NO. NPF-22 PLA-7707 TALEN~
ENERGY 10 CFR 50.73 Docket No. 50-387 50-388 Attached is Licensee Event Report (LER) 50-387(388)/2018-002-00. This LER is reporting an event which caused a loss of secondary containment differential pressure that was determined to be reportable in accordance with 10 CFR 50.73(a)(2)(v)(C) as a condition that could have prevented fulfilment of a safety function.
There were no actual consequences to the health and safety of the public as a result of this event.
This letter contains no new regulatory commitments.
Should you have any questions regarding this submittal, please contact Mr. Jason Jennings, Manager-Nuclear Regulatory Affairs at (570) 542-3155.
Attachment: LER 50-387(388)/2018-002-00 Copy:
NRC Region I Ms. T. E. Hood, NRC Project Manager Ms. L. H. Micewski, NRC Sr. Resident Inspector Mr. M. Shields, PA DEP/BRP
Electronic Copy:
B. Berryman M. M. Thorpe-Kavanaugh (NSRB)
J. R. Jennings D. J. LaMarca K. Brown T. L. Martin M. J.Murphy L. G. Oberrender G. S. Lubinsky DCS (DBD) Document Control Desk PLA-7707
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)
, the NRC may not conduct or sponsor, and a oerson is not required to respond to, the information collection.
3.Page Susquehanna Steam Electric Station Unit 1 05000387 1 OF3
- 4. Title Loss of Secondary Containment Differential Pressure Following Surveillance Testing
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Sequential Rev Facility Name Docket Number Month Day Year Year Month Day Year Susquehanna Steam Electric Station Unit 2 Number No.
05000388 04 03 2018 2018 002 00 05 30 2018 Facility Name Docket Number N/A 05000
- 9. Operating Mode Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On April 03, 2018 at approximately 00:19, the Susquehanna control room received indication of a loss of Secondary Containment Zone 3 differential pressure, noting differential pressure less than 0.25 inches water gauge (WG). As a result, Technical Specification 3.6.4.1 Surveillance Requirement 3.6.4.1.1 was not met.
The alarm came in during Unit 1 surveillance testing.
The condition is being reported in accordance with 10 CFR 50. 73(a)(2)(v)(C) as an event or condition that could have prevented fulfillment of a safety function. The condition was previously reported on April 03, 2018, at 02:53 in accordance with 10 CFR 50.72(b)(3)(v)(C) in EN#53310.
The direct cause of this event was due to vendor workmanship resulting in a missing cotter pin that prevented the Unit 2, Zone 3 Supply Fan breaker from closing and remaining closed.
Corrective actions include installation of cotter pin on the Unit 2, Zone 3 Supply Fan breaker, replacement of electronic control device, and addition of step to identified plant procedures to ensure a retaining pin is installed prior to installation of refurbished breakers.
There were no actual consequences to the health and safety of the public as a result of this event.
NRC FORM 366 (04-2018)
CONDITIONS PRIOR TO EVENT
Unit 1 - Mode 5, 0 percent Rated Thermal Power Unit 2 - Mode 1, approximately 1 00 percent Rated Thermal Power There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event. Unit 1 was in a refueling outage and Secondary Containment Zone 1 was relaxed.
EVENT DESCRIPTION
On April 03, 2018 at approximately 00:19, the Susquehanna control room received indication of a loss of Secondary Containment Zone 3 HVAC [EllS: NG] differential pressure, noting differential pressure (dP) less than 0.25 inches water gauge (WG). As a result, Technical Specification (TS) 3.6.4.1 Surveillance Requirement 3.6.4.1.1 was not met. The alarm came in during Unit 1 surveillance testing.
An abbreviated timeline of the April 03, 2018 events is as follows:
00:01: Unit 1 surveillance testing initiated.
00:19: Unit 2 Control Room received Reactor Building HVAC and Zone 3 alarms. Operations entered applicable Unit 1 and Unit 2 TS 3.6.4.1 action statements due to loss of Zone 3 dP resulting from fan oscillations.
00:29- 00:40: Unit 1 and Unit 2, Zone 3 fans [EllS: FAN] observed cycling. Operator placed all Zone 3 fans in STOP.
01:19: Operations determined Unit 2, Zone 3 fans [EllS: FAN] could not maintain dP.
01:35: Unit 1, Zone 3 was restarted and maintained appropriate dP.
01:45: Operations exited applicable TS 3.6.4.1 action statements.
During attempts to restart Unit 2, Zone 3 Supply Fan 2V212B [EllS: FAN], the fan was unable to start because the Unit 2, Zone 3 Supply Fan Breaker 2B28033 [EllS: BKR] could not close. The investigation concluded that the electronic control device was not functioning correctly. During the replacement of the control device, the axial pin that connects the trip paddle to the breaker was found to be improperly positioned such that it prevented the breaker from closing and remaining closed. The axial pin requires a cotter pin to keep the axial pin in place when the breaker closes and to remain closed. A cotter pin was installed and the electronic control device was replaced.
The condition is being reported in accordance with 10 CFR 50. 73(a)(2)(v)(C) as an event or condition that could have prevented fulfillment of a safety function. The condition was previously reported on April 03, 2018, at 02:53 in accordance with 10 CFR 50.72(b)(3)(v)(C) in EN#53310.
~----------------------------------------------------------------------------~, Page 2 of 3 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing this form http://vvww. nrc. g ov/readi nq-rm/doc-collections/nu reqs/staff/sr1 022/r3D
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
YEAR Susquehanna Steam Electric Station Unit 1 05000-387 2018
CAUSE OF EVENT
- 3. LER NUMBER SEQUENTIAL NUMBER
. 002 REV NO.
. 00 The direct cause of this event was due to vendor workmanship resulting in a missing cotter pin that prevented the Unit 2, Zone 3 Supply Fan breaker from closing and remaining closed.
ANALYSIS/SAFETY SIGNIFICANCE
Based on engineering analysis of the event, secondary containment could have performed its safety function of isolating as assumed in the accident analysis and of re-establishing 0.25 inches of vacuum WG (drawdown) within the assumed accident analysis time (1 0 minutes).
This event will not be counted as a safety system functional failure (SSFF) for the NRC performance indicator based on the engineering analysis supporting the system's ability to fulfill the safety function.
CORRECTIVE ACTIONS
Pertinent corrective actions include the following:
- 1. Installation of cotter pin on the Unit 2, Zone 3 Supply Fan breaker and replacement of electronic control device (Action Complete).
- 2. Addition of step to identified plant procedures to ensure a retaining pin is installed prior to installation of refurbished breakers where applicable.
PREVIOUS SIMILAR EVENTS
The following are recent LERs involving loss of secondary containment:
LER 50-387(388)/2017-007-01, "Secondary Containment Declared Inoperable Due to the Opening of a Plenum,"
dated May 04, 2018.
LER 50-388(387)/2018-001-00, "Loss of Secondary Containment Differential Pressure During Entry into Unit 2 Zone 3 Exhaust Plenum," dated April 11, 2018.
LER 50-388(387)/2017-009-01, "Secondary Containment Declared Inoperable Due to Trip of Zone II Equipment Exhaust Fan," dated February 12, 2018.
LER 50-388(387)/2017-007-00, "Secondary Containment Declared Inoperable Due to Supply Air Flow," dated October 09, 017.
LER 50-388(387)/2017 -006-00, "Secondary Containment Declared Inoperable Due to Trip of Zone II Exhaust Fan," dated September 06, 2017.
LER 50-388(387)/2017-005-00, "Secondary Containment Declared Inoperable Due to Trip of Zone Ill Filtered Exhaust Fan," dated August 18, 2017.
LER 50-387(388)/2017-004-00, "Secondary Containment Declared Inoperable Due to Failure of an Exhaust Fan Breaker," dated August 04, 2017.
LER 50-387(388)/2017-003-00, "Loss of Secondary Containment Zone 3 Due to Fan Trip," dated May 05, 2017. Page 3 of 3