05000346/LER-2019-002, Auxiliary Feedwater Trains Inoperable Due to Loss of Train Separation from Door Being Left Open
| ML19295F430 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/18/2019 |
| From: | Bezilla M FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-19-208 LER 2019-002-00 | |
| Download: ML19295F430 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix) 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 |
| 3462019002R00 - NRC Website | |
text
FENOC' FirstEnergy Nuclear Operating Company 5501 North State Route 2 Oak Harbor, Ohio 43449 Mark a. Bezilla Vice President. Nuclear October 18, 2019 L-19-208 ATTN: Document Control Desk United States Nuclear Regulatory Commission Washington, D.C. 20555-0001
Subject:
Davis-Besse Nuclear Power Station, Unit 1 Docket Number 50-346, License Number NPF-3 Licensee Event Report 2019-002 10 CFR 50.73 Enclosed is Licensee Event Report (LER) 2019-002, "Auxiliary Feedwater Trains Inoperable due to Loss of Train Separation from Door Being Left Open~" This event is being reported pursuant to 10 CFR 50. 73(a)(2)(v)(B) and 10 CFR 50. 73(a)(2)(vii)(B).
419-321-7676 There are no regulatory commitments contained in this letter or its enclosure. The actions described represent intended or planned actions and are described for information only.
If there are any questions or if additional information is required, please contact Mr.
James M. Vetter, Manager-Site Regulatory Compliance (Acting), at (419) 321-7393.
Sincerely, tJuji!J Mark B. Bezilla/
gae Enclosure: LER 2019-002 cc: NRC Region Ill Administrator NRC Resident Inspector NRR Project Manager Utility Radiological Safety Board
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 (04-2018)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
3.Page Davis-Besse Nuclear Power Station, Unit 1 05000 346 1 OF 5
- 4. Title:
Auxiliary Feedwater Trains Inoperable due to Loss of Train Separation from Door Being Left Open
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved I
Sequential I Rev Facility Name Docket Number Month Day Year Year Number No.
Month Day Year 05000 Facility Name Docket Number 08 19 2019 2019 -
002 00 10 18 2019 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)(ii){A)
D 50.73(a)(2)(viii)(A) 1 D 20.2201(d)
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)
D 20.2203(a)(4)
D 50. 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 50.36(c)(2)
[8'.I 50.73(a)(2)(v)(B)
D 73.71 (a)(5)
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.77(a)(1) 100 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)
D 50. 73(a)(2)(i)(B)
[8'.I 50. 73(a)(2)(vii)
D 73.77(a)(2)(ii)
D 50. 73(a)(2)(i)(C)
D Other (Specify in Abstract below or in
==DESCRIPTION OF EVENT==YEAR 2019
- 3. LER NUMBER SEQUENTIAL NUMBER 002 REV NO.
00 Following a task preview in the Maintenance Services Shop, two (2) Maintenance Services and two (2)
Quality Control (QC) personnel convened at the hatch, Door 363, that allows access to AFW Pump 2 Room.
The hatch was opened by the dispatched Security Officer and latched open. The four (4) workers swiped their badges and entered through Door 363 and went down the stairs, traversing through AFW Pump 2 Room to Door 215. Door 215 is a watertight door that provides normal access to AFW Pump 1 Room. Door 215 was then opened and the workers proceeded through, leaving the door open. The Central Alarm Station (GAS) received the appropriate alarm upon the door being opened at 0811. A card reader does not control access into/out of Door 215; the door is monitored by GAS which receives an alarm upon the door being opened and a reset when closed.
Following piping insulation removal, the Maintenance Services workers returned to their shop to wait for the QC workers to complete their inspections before reinstalling the insulation. After the Maintenance Services workers left the area, a Security Officer on patrol entered Door 363 at 0858 and descended the stairs, observing one of the QC workers going between the two rooms, with Door 215 open. The Security Officer called the GAS Officer and reported the door check was complete and left the area at 0900. Approximately twenty-two (22) minutes later, 0922, one additional QC worker also left the area with the Door 215 remaining open. At 0924 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.51582e-4 months <br />, a Plant Operator performing a zone tour swiped their badge at Door 363 and when arriving at Door 215, noted it was open and unattended. The Operator contacted Shift Management, who directed the Operator to close Door 215. Door 215 was subsequently closed, and a reset alarm was received at GAS at 0926.
CAUSE OF EVENT
The cause of Door 215 being left open for approximately 75 minutes without permission from Operations was worker inattention to door signage, resulting in non-adherence to door usage requirements. Workers did not read and/or adhere to door signage in accordance with Site/Management expectations or procedural guidance.
A contributing cause for this event was that Door 215 monitoring by Security was not completed in accordance with procedure, contributing to the door remaining open for longer than allowed for ingress or egress.
ANALYSIS OF EVENT
The two Auxiliary Feedwater Trains are separated by Door 215, which serves as a Fire, Flood, Tornado, Security, and High Energy Line Break (HELB) barrier. The door allows transit between the two vital area rooms. With Door 215 open, the design/licensing basis regarding breaks of a Main Steam Line or Feedwater line in the AFW Rooms was no longer met, as the wall and "pressure door" are credited for separating the two rooms to protect the adjacent AFW train. As a result, both AFW trains were declared inoperable due to the loss of train separation in accordance with LCO 3. 7.5.
Operability of the AFW System was restored when the door was closed at 0926.
==ANALYSIS OF EVENT==The non-safety grade Motor-Driven Feedwater Pump remained Operable during this time; additionally, the beyond-design basis diesel-driven Emergency Feedwater Pump also remained available.
Both AFW trains were functional during the inoperable window but were vulnerable to a common cause failure from various environmental causes. Of concern is a High Energy Line Break (HELB) which Door 215 functions to protect against. The Probabilistic Risk Assessment (PRA) does not account for specific HELB breaks, and thus a bounding assessment of risk was performed.
Additional hazards, including flooding and internal fires, have the capability to impact both AFW trains while the door was open. Only scenarios where an internal fire or flood that affected one of the two compartments are considered to have been impacted by the deficient condition.
00 The plant risk associated with the inoperable AFW trains is considered of very low safety significance. This is based on the change in core damage frequency for the event during total 75 minutes that the degraded condition existed. A sensitivity with the draft NFPA 805 model evaluated for Internal Fires indicated this event is overall considered of very low safety significance as well.
Reportability Discussion:
With Door 215 open, both trains of AFW were rendered inoperable per TS LCO 3.7.5. This resulted in a loss of Safety Function for the AFW System, which was reported per 10 CFR 50.72(b)(3)(v)(B) at 1446 hours0.0167 days <br />0.402 hours <br />0.00239 weeks <br />5.50203e-4 months <br /> on August 19, 2019; refer to Event Notification 54229. This issue is being reported as an event or condition that could have prevented fulfillment of a safety function of system needed to remove residual heat per 10 CFR 50. 73(a)(2)(v)(B) and as a common cause inoperability of independent trains per 10 CFR
- 50. 73(a)(2}(vii)(B).
CORRECTIVE ACTIONS
Completed Actions:
The workers involved were removed from the field and coached on the importance/requirements of vital area doors. The lessons learned by the involved department personnel were documented and presented to management and a stand down communication on the door design, functions and usage was shared with site employees. 2019 Cycle 2 Supervisor Continuing Training (G-SSC-201902_DB) includes discussions of the lessons learned from this event regarding Door 215.
Scheduled Actions:
Site Protection will incorporate additional procedural guidance on the monitoring of Door 215.
PREVIOUS SIMILAR EVENTS
- 2. DOCKET NUMBER 346 YEAR 2019
- 3. LER NUMBER SEQUENTIAL NUMBER
~
002 DBNPS Licensee Event Report (LER) 2017-002 reported the inoperability of AFW Train 1 for approximately 87 days with the plant operating in Mode 1. In addition, during the time AFW Train 1 was Inoperable, AFW 2 was Inoperable for maintenance and testing on multiple occasions. The corrective actions taken in response to the 2017 event included ensuring proper oil sight glass markings were made on both AFW Pump Turbine inboard bearings and direct observation of correct sight glass level markings on outboard bearings during the next refueling outage in March 2018. Lubrication Manual Data Sheets were also revised to include bearing oil sight glass minimum and maximum level dimensions as well as adding a reference to the Lubrication Manual in Preventive Maintenance Activities. The actions in response to the 2017 event are unrelated to the cause of the event being reported in this LER and there have been no LERs at DBNPS involving a loss of a Safety Function related to door control in the past three years.
REV NO.
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