05000458/LER-2013-002, Regarding Potential Loss of Safety Function of Secondary Containment Due to Employee Leaving a Door Unsecured
| ML13317B627 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 11/06/2013 |
| From: | Olson E Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RBG-47406 LER 13-002-00 | |
| Download: ML13317B627 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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)(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 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4582013002R00 - NRC Website | |
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S' Entergy Entergy Operations, Inc.
River Bend Station 5485 U. S. Highway 61 N St. Francisville, LA 70775 Tel 225 381 4374 Fax 225 381 4872 eolson@entergy.com Eric W. Olson Site Vice President RBG-47406 November 6, 2013 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Subject:
Licensee Event Report 50-458 / 2013-002-00 River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47 RBF1-13-0142
Dear Sir or Madam:
In accordance with 10 CFR 50.73, enclosed is the subject Licensee Event Report.
This document contains no commitments. If you have any questions, please contact Mr. Joseph Clark at 225-381-4177.
Sincerely, EWO/dhw Enclosure TZA
Licensee Event Report 50-458 / 2013-002-00 November 6, 2013 RBG-47406 Page 2 of 2 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)
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 Emergency Planning and Response Section JiYoung Wiley P.O. Box 4312 Baton Rouge, LA 70821-4312
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010) digits/characters for each block) the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE River Bend Station - Unit I 05000-458 1 OF3
- 4. TITLE Potential Loss of Safety Function of Secondary Containment Due to Employee Leaving a Door Unsecured
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SSEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
n/a 05000 FACILITY NAME DOCKET NUMBER 09 19 2013 2013-002-00 11 6
2013 n/a 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1 El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
[1 50.73(a)(2)(viii)(B)
E] 20.2203(a)(2)(i)
Dl 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
[3 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL [I 20.2203(a)(2)(ii)
[E 50.36(c)(1)(ii)(A)
[: 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
[E 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71 (a)(4) 100 El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5)
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
Z 50.73(a)(2)(v)(C) 0l OTHER El 20.2203(a)(2)(vi)
E3 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER FACILITY NAME TELEPHONE NUMBER (Include Area Code)
Joseph A. Clark, Manager - Licensing 225-381-4177MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX FACTURECR TO EPIX n/a
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION
[:]YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
O NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On September 19, 2013, at approximately 1437 CDT, with the plant operating at 100 % power, a door in the secondary containment pressure boundary was left unsecured by an employee entering the building. Upon closing the door, the employee mistakenly rotated the handwheel slightly, caused the latch bolts to extend partially. The latch bolts then contacted the outside of the keepers in the door frame, blocking the door open.
The employee did not notice that the door was slightly open when he rotated the handwheel to the "closed" position, and then did not properly 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. This event was caused by improper use of human performance techniques by the employee, in that he failed to confirm that he had operated the door correctly. This event is being reported in accordance with 10 CFR 50.73(a)(2)(v) as a condition that could have caused the loss of the safety function of the secondary containment pressure boundary. Since the plant's safety analysis does not assume the function of secondary containment for the first 30 minutes of the design basis accident, safety function was actually maintained. This event was of minimal significance with regard to the health and safety of the public.
NRC FORM 366 (10-2010)LICENSEE EVENT REPORT (LER)
U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE YEAR SEQUENTIAL REV.
I NUMBER NO.
River Bend Station - Unit 1 05000 -458 2 OF 3 2013 - 002 -
00 REPORTED CONDITION On September 19, 2013, at approximately 1437 CDT, with the plant operating at 100% power, a door (**DR**) in the auxiliary building (NF) pressure boundary was left unsecured by an employee entering the building. Upon closing the door, the employee mistakenly rotated the handwheel slightly, caused the latch bolts to extend partially. The latch bolts then contacted the outside of the keepers in the door frame, blocking the door open. The employee did not notice that the door was slightly open when he rotated the handwheel 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.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(v) as an event that could have caused the loss of the 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 limiting 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, and that fission products entrapped within the secondary containment structures will be treated prior to discharge to the environment.
The 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 door compromises the integrity of the pressure boundary.
CAUSAL ANALYSIS This event occurred as two employees were entering the building to perform an inspection. The first person, a radiation protection technician, opened the door and entered the building. The second person, a contract engineer, followed the technician and assumed responsibility for securing the door. The engineer had attended a pre-job brief for his task, including both a general discussion of door safety and operating experience related specifically to the subject door. Prior to entering the auxiliary building, the radiation protection technician observed that the engineer properly operated other doors.LICENSEE EVENT REPORT (LER)
U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE YEAR SEQUENTIAL REV.
NUMBER NO.
River Bend Station - Unit 1 05000 -458 3 OF 3 2013 -- 002-00 A human performance error review identified a perceived time pressure and overconfidence as the applicable error traps. Since two individuals traversed the door during one entry, the contract engineer felt time pressure to close the door before the security alarm time delay was exceeded.
After closing the door and checking that the handwheel was locked, the engineer displayed overconfidence by assuming the door was properly secured without pushing against the door to verify the latch bolts were engaged. The engineer stated that he was aware that verification of door security includes challenging the handwheel by attempting to rotate it, as well as challenging the door by pushing or pulling on it.
CORRECTIVE ACTION TO PREVENT RECURRENCE The following actions have been completed to prevent a recurrence of this event. These actions are documented in the station's corrective action program.
- 1. A briefing memorandum was issued by the plant manager to all site personnel.
- 2. A stand-down was conducted by the site engineering department, as well as the contractor's organization, to review the event and its causes.
- 3. Focused observations were conducted in the plant to confirm that all door operations were being performed in accordance with site standards and expectations.
SAFETY SIGNIFICANCE
The 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 capable of being secured) within 20 minutes of the time of the 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 Component Identification codes are annotated as (**XX**).)