05000458/LER-1917-009, Regarding Potential Loss of Safety Function of Secondary Containment Due to Unsecured Personnel Door
| ML17325A996 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 11/13/2017 |
| From: | Maguire W Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RBF1-17-0138, RBG-47800 LER 17-009-00 | |
| Download: ML17325A996 (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)(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)(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) |
| 4581917009R00 - NRC Website | |
text
- ' *
<:!PEnterP
bJ@
RBG-47800 November 13, 2017 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555
Subject:
RBF1-17-0138 Licensee Event Report 50-458 I 2017-009-00 River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47
Dear Sir or Madam:
Entergy Operations, Inc.
River Bend Station
. 5485 U.S. Highway 61 N St Francisville, LA 70775 Tel 225-381-4374 William F. Maguire Site Vice President In accordance with 1 O CFR 50.73, enclosed is the subject Licensee Event Report. This document contains no commitments. If you have any questions, please contact Mr. Tim Schenk at 225-381-4177.,
Sincerely, WFM Enclosure cc:
U. S. Nuclear Regulatory Commission Region IV 1600 East Lamar Blvd.
Arlington, TX 76011-4511 NRC Sr. Resident Inspector P. 0. Box 1050 St. Francisville, LA 70775 INPO (via ICES reporting)
Licensee Event Report 50-458 / 2017-009-00 November 13, 2017 RBG-47800 Page 2 of 2 Central Records Clerk Public Utility Commission of Texas 1701 N. Congress Ave.
Austin, TX 78711-3326 Department of Environmental Quality Office of Environmental Compliance Radiological l::mergency Planning and Response Section Ji Young Wiley P.O. Box 4312 Baton Rouge, LA 70821-4312
NRCFOR!V( 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017) httQ://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022lr3D the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME
~- DOCKET NUMBER
~- PAGE River Bend Station...:.. Unit 1 05000-458 1 OF4
- 4. TITLE Potential Loss of Safetv Function of Secondarv Containment due to Unsecured Personnel Door
- 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 NUMBER NO.
05000 09 27 2017 2017 009 00 11 13 2017 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: Check all that aoolv) 1 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 (d)
D 20.2203(a)(3)(ii) 0 50.73(a.)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1)
D 20.2203(a)(4)
D so.fa(a)(2)(iii) 0 50.73(a)(2)(ix)(A)
D 20:2203(a)(2)(il D so.36(c)(1)(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LE.VEL D 20:2203(a)(2)(ii)
D so:36(c)(1 )(ii)(A) 0 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)(5) 85 D 20.2203(a)(2)(iv)
D so.46(a)(3)(ii)
[8] 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)
D 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) 00THER Specify in Abstract below or in NRG Form 366A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT rrLEPHONE NUMBER (Include Area Code)
- - lfim Schenk, Manager - Requlatory Assurance
~25-381-4177 CAUSE SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TOEPIX na
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR D YES (If yes, complete 15. EXPECTED SUBMISSION DATE) 1:.8] NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On September 27, 2017, at approximately 10:00 a.m. CDT, with the plant operating at 85 percent power, a door in the auxiliary building pressure boundary was left unsecured by an employee entering the building. The employee failed to fully close the door, and then did not properly challenge the door to confirm its security prior to leaving the area. A security officer responded to the resulting alarm, and fully closed the door approximately four minutes later. Since the worker had sufficient experience with watertight doors to know their proper operation, this event is considered a skill-based error caused by over-confidence and improper assumptions. Having successfully used such doors numerous times, the worker was confident in the ability to do so. The effort to check the door's security by pushing it failed, likely due to its heavy mass.
A briefing memorandum was issued from the general manager to site personnel. Tamper alarms were installed on all watertight doors in the secondary containment boundary to provide an audible indication that the door is open.
~dministrative controls have been instituted to schedule routine battery replacements.
NRG FORM 366 (04-2017)
REPORTED CONDITION SEQUENTIAL NUMBER 009 REV NO.
00 On September 27, 2017, at approximately 10:00 a.m. CDT, with the plant operating at 85 percent power, a door (**DR**)
in the auxiliary building [NF] pressure boundary was left unsecured by an employee entering the building. The employee failed to fully close the door, and then did not properly challenge the door to confirm its security prior to leaving the area. A security officer responded to the resulting alarm, and fully closed the door approximately four minutes later.
This event is being reported in a.ccordance witr 10 CFR 50.73(a)(2)(v)(C) as*an event that could have caused the.loss of
~he safety function of the secondary containment pressure boundary.
BACKGROUND
\\
The auxiliary building is part of the secondary containment pressure boundary. The event for which credit is taken for secondary containment is a loss of coolant accident. The secondary containment performs no active function in response to this event. However, its leak tightness is required to ensure that the release of radioactive materials from the primary containment is restricted to those leakage paths and associated leakage rates assumed in the accident analysis, aryd that fission products entrapped within the secondary containment structures will be treated prior to discharge to the environment.
lfhe access doors in the auxiliary building pressure boundary have no redundancy: That is, each passageway contains only one door, not two doors in an airlock arrangement. As such, one unsecured do<;>r compromises the integrity of the pressure boundary.
CAUSAL ANALYSIS lfhe door was mis-operated by a contract worker with significant experience at River Bend, who had successfully traversed such doors in the past. The pre-job brief for the work to be performed in the auxiliary building did not include a specific discussion of secondary containment doors.
Four workers were traversing the door sequentially. The first worker swiped the card reader to open the door, and all the following workers swiped the card reader before entering the building to assure security accountability. The last person entering the door is responsible for closing it properly to secure the boundary. In this instance, the last person was being assisted by the previous worker who pulled on the door handle, while the last worker pulled on the door lock hand wheel. The worker pulling on the hand wheel inadvertently rotated it, causing the latch bolts to extend slightly.
The latch bolts contacted the door frame outside of their receivers, preventing the door from being closed completely.
Thinking that the door was properly closed, the worker holding the hand wheel rotated it fully, and the worker pulling the handle failed to notice that the door was not in contact with the seating surface in the frame. The worker then made an effort to assure the door's security by pushing in the open direction, but failed to move it. They then departed the area, leaving the door unsecured. Page 2 of 4 (04-2017)
. U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020
, the NRC may not conduct or sponsor, and a. person is not required to respond to, the jnformation collection.
3, LER NUMBER YEAR River Bend*Station - Unit 1 05000-458 2017 SEQUENTIAL NUMBER 009 REV NO.
00 Since the worker had sufficient experience with watertight doors to know their proper operation, this event is considered a skill-based error caused by over-confidence and improper assumptions. Having successfully used such doors numerous times, the worker was confident in the ability to do so. The effort to check the door's security by pushing it failed, likely due to its heavy mass.
CORRECTIVE ACTION TO PREVENT RECURRENCE rThe following actions have been completed to prevent a recurrence of this event. These actions are documented in the station's ~orrective action p(cigram.
A briefing memorandum was issued from the general manager to site personnel.
Tamper alarms were instaUed on all watertight doors in the secondary containment boundary to provide an audible.
indication that the door is open. Administrative controls have been instituted to schedule routine battery replacements.
PREVIOUS OCCURRENCE EVALU.ATION
~ similar event was reported.bY RBS in LER 050/458-2013-002-00. On September 19, 2013, at approximately 1437 CDT, with the plant operating at 100% power, the same door was left unsecured by an employee entering the auxiliary buildir:,g. Upon closing the door, the employee mistaken,ly rotated the hand wheel while pulling ori.it, caused the latch bolts to exte.nd partially. The latch bolts then contacted the door frame outside the receivers, blocking the doo_r open slightly. The employee did not notice that the door was slightly open when he rotated the hand wheel to the "closed" position, and then did not properly challenge the door to confirm its security prior to leaving the area. A security officer responded to the resultant alarm, and fully closed the door approximately four minutes later. One of the corrective actions taken in response to that event was to update the computer-based training module us'ed in the process for granting unescorted access to the site to include specific material related to the operation of watertight secondary containment doors. The skill-based error of failing to assure the security of the door occurred d~spite having successfully performed the task numerous times in the past. Both workers at the scene failed to adequately self-check their actions.
An additional corrective action in 2013 was to procure a commercially-available audible door tamper alarm that could be installed without any modification to the door itself, as well as other similar doors in the auxiliary building. These alarm modules were maintained for approximately two years, but no rigorous programmatic control was put into place at the time to assure their continued functionality, and the alarms modules were eventually removed.
SAFETY SIGNIFICANCE
rThe River Bend Updated Safety Analysis Report describes the sequence of events postulated to occur following, a loss of coolant accident (LOCA). Part of that analysis is a projection of the maximum radiation dose received by a person at the site boundary. The LOCA dose calculation assumes that the standby gas treatment system is initiated 20 minutes into the event, and that secondary containment is at the required negative pressure within 30 minutes, such that filtration may be credited. As such, the safety function of secondary containment is maintained as long as the boundary is secured (or Page 3 of 4 (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 htto://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/j
, the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITYNAME
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR River Bend Station - Unit 1 05000-458 2017 SEQUENTIAL NUMBER 009 REV NO.
00 capable of being secured) within 20 minutes of the time ofthe security alarm_ Since the subject door was secured within approximately four minutes of the time of the alarm, the safety function of secondary containment was actually maintained. This event was of minimal significance with respect to the health and safety of the public.
(NOTE: Energy Industry Identification System component function identifier and system name of each component or system referred to in the LER are annotated as (**XX**) and [XX], respectively.) Page 4 of 4